Plank takes a long time to unhide (and sometimes doesn't at all)

Plank is acting weirdly: It usually takes a long time to unhide when I hover around the bottom edge of the screen, around a few seconds.

Sometimes, also, it won't unhide, no matter how long I wait moving the mouse horizontally on the bottom edge. On these cases, however, the moment I move the mouse a little bit vertically, it will appear.

There also occur situations where it appears instantaneously when I move the mouse to the edge, but also hides just as fast, and stays hidden unless I move the mouse out of the area and in again.

I tried uninstalling (with purging) plank and reinstalling, but nothing changed.

I have a dual-monitor setup and plank only appears on the primary monitor right now.

$ plank --version
0.11.3

$ uname -ra
Linux desktop-linux 4.4.0-77-generic #98-Ubuntu SMP Wed Apr 26 08:34:02 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

$ cat /etc/issue
elementary OS Loki \n \l

$ wmctrl -m
Name: Mutter(Gala)
Class: N/A
PID: N/A
Window manager's "showing the desktop" mode: N/A

$ X -version
X.Org X Server 1.18.4
Release Date: 2016-07-19
X Protocol Version 11, Revision 0
Build Operating System: Linux 4.4.0-45-generic x86_64 Ubuntu
Current Operating System: Linux desktop-linux 4.4.0-77-generic #98-Ubuntu SMP Wed Apr 26 08:34:02 UTC 2017 x86_64
Kernel command line: BOOT_IMAGE=/boot/vmlinuz-4.4.0-77-generic.efi.signed root=UUID=144757dd-a7cb-4c22-9573-95b26dca35fe ro quiet splash vt.handoff=7
Build Date: 02 November 2016 10:06:10PM
xorg-server 2:1.18.4-0ubuntu0.2 (For technical support please see http://www.ubuntu.com/support)
Current version of pixman: 0.33.6

$ nvidia-smi
Fri May 12 15:03:47 2017
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 381.22 Driver Version: 381.22 |
|-------------------------------+----------------------+----------------------+
| GPU Name Persistence-M| Bus-Id Disp.A | Volatile Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap| Memory-Usage | GPU-Util Compute M. |
|===============================+======================+======================|
| 0 GeForce GTX 106... Off | 0000:01:00.0 On | N/A |
| 27% 55C P0 32W / 120W | 302MiB / 6069MiB | 1% Default |
+-------------------------------+----------------------+----------------------+

+-----------------------------------------------------------------------------+
| Processes: GPU Memory |
| GPU PID Type Process name Usage |
|=============================================================================|
| 0 1204 G /usr/lib/xorg/Xorg 213MiB |
| 0 2456 G gala 30MiB |
| 0 3460 G ...el-token=F391323765ED998697F471D60764DE21 56MiB |
+-----------------------------------------------------------------------------+

$ killall plank && plank -d
[WARN 15:04:39.222494] [Gtk] Theme parsing error: gtk-widgets.css:2045:14: 'min-height' is not a valid property name
[WARN 15:04:39.226761] [Gtk] Theme parsing error: gtk-widgets.css:2046:13: 'min-width' is not a valid property name
[WARN 15:04:39.231026] [Gtk] Theme parsing error: gtk-widgets.css:2051:13: 'min-width' is not a valid property name
[DEBUG 15:04:39.241142] [Gtk] Connecting to session manager
[INFO 15:04:39.241595] [AbstractMain:229] Plank version: 0.11.3
[INFO 15:04:39.241611] [AbstractMain:230] Kernel version: 4.4.0-77-generic
[INFO 15:04:39.241622] [AbstractMain:231] GLib version: 2.48.2 (2.48.1)
[INFO 15:04:39.241635] [AbstractMain:234] GTK+ version: 3.18.9 (3.18.9)
[INFO 15:04:39.241645] [AbstractMain:237] Wnck version: 3.14.1
[INFO 15:04:39.241660] [AbstractMain:238] Cairo version: 1.14.6
[INFO 15:04:39.241670] [AbstractMain:239] Pango version: 1.38.1
[INFO 15:04:39.241681] [AbstractMain:241] + Cairo/Gtk+ HiDPI support enabled
[INFO 15:04:39.241690] [AbstractMain:244] + Dynamic Quicklists support enabled
[INFO 15:04:39.241699] [AbstractMain:247] + XInput Barriers support enabled
[INFO 15:04:39.241711] [AbstractMain:252] + Icon-Zoom support disabled ( Thanks to https://www.google.com/patents/US7434177 )
[WARN 15:04:39.241727] [Environment:161] XDG_SESSION_CLASS not set in this environment!
[INFO 15:04:39.245773] [WindowControl:68] Window-manager: Mutter(Gala)
[DEBUG 15:04:39.246203] [DockletManager:204] Loading module '/usr/lib/x86_64-linux-gnu/plank/docklets/libdocklet-clock.so'
[INFO 15:04:39.246231] [DockletManager:107] Docklet 'clock' registered
[DEBUG 15:04:39.246516] [DockletManager:204] Loading module '/usr/lib/x86_64-linux-gnu/plank/docklets/libdocklet-desktop.so'
[INFO 15:04:39.246540] [DockletManager:107] Docklet 'desktop' registered
[DEBUG 15:04:39.246839] [DockletManager:204] Loading module '/usr/lib/x86_64-linux-gnu/plank/docklets/libdocklet-trash.so'
[INFO 15:04:39.246865] [DockletManager:107] Docklet 'trash' registered
[DEBUG 15:04:39.247149] [DockletManager:204] Loading module '/usr/lib/x86_64-linux-gnu/plank/docklets/libdocklet-clippy.so'
[INFO 15:04:39.247173] [DockletManager:107] Docklet 'clippy' registered
[DEBUG 15:04:39.247457] [DockletManager:204] Loading module '/usr/lib/x86_64-linux-gnu/plank/docklets/libdocklet-cpumonitor.so'
[INFO 15:04:39.247481] [DockletManager:107] Docklet 'cpumonitor' registered
[INFO 15:04:39.247710] [AbstractMain:303] Running with 2 docks ('DVI-D-0', 'DVI-D-1')
[DEBUG 15:04:39.247748] [DockController:79] Create dock 'DVI-D-0' (config_folder = /home/delisson/.config/plank/DVI-D-0)
[DEBUG 15:04:39.247853] [Settings:53] Bind 'PlankDockPreferences' to '/net/launchpad/plank/docks/DVI-D-0/'
[CRITICAL 15:04:39.257168] [GLib-GIO] g_dbus_connection_register_object: assertion 'object_path != NULL && g_variant_is_object_path (object_path)' failed
[CRITICAL 15:04:39.264681] [GLib-GIO] g_dbus_connection_emit_signal: assertion 'object_path != NULL && g_variant_is_object_path (object_path)' failed
[WARN 15:04:39.271539] [Gtk] Theme parsing error: gtk-widgets.css:2045:14: 'min-height' is not a valid property name
[WARN 15:04:39.275866] [Gtk] Theme parsing error: gtk-widgets.css:2046:13: 'min-width' is not a valid property name
[WARN 15:04:39.280192] [Gtk] Theme parsing error: gtk-widgets.css:2051:13: 'min-width' is not a valid property name
[WARN 15:04:39.293682] [Preferences:192] '/usr/share/themes/elementary/plank/dock.theme' is read-only!
[DEBUG 15:04:39.293702] [Preferences:349] Loading preferences from file '/usr/share/themes/elementary/plank/dock.theme'
[DEBUG 15:04:39.294506] [ItemFactory:176] Loading dock elements from '/home/delisson/.config/plank/DVI-D-0/launchers'
[DEBUG 15:04:39.294746] [Preferences:349] Loading preferences from file '/home/delisson/.config/plank/DVI-D-0/launchers/google-chrome.dockitem'
[DEBUG 15:04:39.295107] [Preferences:349] Loading preferences from file '/home/delisson/.config/plank/DVI-D-0/launchers/org.pantheon.switchboard.dockitem'
[DEBUG 15:04:39.309520] [Unity:164] Initializing LauncherEntry support
[INFO 15:04:39.311096] [HideManager:618] Barriers enabled (XInput 2.3 support)
[DEBUG 15:04:39.311152] [PositionManager:665] Without draw_values there is trouble ahead
[DEBUG 15:04:39.311503] [HideManager:746] Barrier: 2759,1080 - 3011,1080
[DEBUG 15:04:39.311946] [Settings:53] Bind 'PlankPantheonDesktopNotifications' to '/org/pantheon/desktop/gala/notifications/'
[DEBUG 15:04:39.312363] [DockController:79] Create dock 'DVI-D-1' (config_folder = /home/delisson/.config/plank/DVI-D-1)
[DEBUG 15:04:39.312404] [Settings:53] Bind 'PlankDockPreferences' to '/net/launchpad/plank/docks/DVI-D-1/'
[CRITICAL 15:04:39.321339] [GLib-GIO] g_dbus_connection_register_object: assertion 'object_path != NULL && g_variant_is_object_path (object_path)' failed
[CRITICAL 15:04:39.328945] [GLib-GIO] g_dbus_connection_emit_signal: assertion 'object_path != NULL && g_variant_is_object_path (object_path)' failed
[WARN 15:04:39.334415] [Preferences:192] '/usr/share/themes/elementary/plank/dock.theme' is read-only!
[DEBUG 15:04:39.334430] [Preferences:349] Loading preferences from file '/usr/share/themes/elementary/plank/dock.theme'
[DEBUG 15:04:39.334600] [ItemFactory:176] Loading dock elements from '/home/delisson/.config/plank/DVI-D-1/launchers'
[DEBUG 15:04:39.334806] [Preferences:349] Loading preferences from file '/home/delisson/.config/plank/DVI-D-1/launchers/google-chrome.dockitem'
[DEBUG 15:04:39.335158] [Preferences:349] Loading preferences from file '/home/delisson/.config/plank/DVI-D-1/launchers/org.pantheon.switchboard.dockitem'
[INFO 15:04:39.337677] [HideManager:618] Barriers enabled (XInput 2.3 support)
[DEBUG 15:04:39.337723] [PositionManager:665] Without draw_values there is trouble ahead
[DEBUG 15:04:39.338547] [Unity:141] com.canonical.Unity lost
[INFO 15:04:39.408646] [DockRenderer:491] Cairo.SurfaceType: XLIB
[INFO 15:04:39.411650] [DockRenderer:491] Cairo.SurfaceType: XLIB
^C[WARN 15:04:58.064421] [AbstractMain:42] Caught signal (2), exiting