Tiny mouse cursor on hidpi screens after logging in

=== System comments

Lenovo Yoga 910 with 13.9" UHD screen.
Bionic Beta 1.
Using 200% scaling.

=== Problem description

Mouse cursor size alternates between tiny size and normal size depending on where I hover the cursor, tiny on top and left bars, normal on desktop and everywhere else.

Of course I expected size to stay normal wherever I positioned the cursor.

=== How to fix the problem

1. Wait for some time or event to pass (have no idea how much/which); AND
2. Click the mouse.

=== Other comments

Must meet both conditions 1 and 2 above in order to fix the issue. That is, cursor size behavior is restored only immediatelly after clicking, but also only after the click has happened after event 1 (and I have no idea what that may be) has passed.

I have noticed this before on 17.10 as well when I briefly tested it last year, but since 1) there are other bug reports dealing with it; and 2) I only use LTS releases anyway, I never got time to test and report it.

This happens on a fresh install of Bionic beta 1. Also today with all updated applied.

=== Required stuff (not sure if it is xorg, if not just ask me and I'll post what you need)

david@buzz:~$ lsb_release -rd
Description: Ubuntu Bionic Beaver (development branch)
Release: 18.04

david@buzz:~$ apt-cache policy xorg
xorg:
  Installed: 1:7.7+19ubuntu5
  Candidate: 1:7.7+19ubuntu5
  Version table:
 *** 1:7.7+19ubuntu5 500
        500 http://us.archive.ubuntu.com/ubuntu bionic/main amd64 Packages
        100 /var/lib/dpkg/status

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: xorg 1:7.7+19ubuntu5
ProcVersionSignature: Ubuntu 4.15.0-12.13-generic 4.15.7
Uname: Linux 4.15.0-12-generic x86_64
ApportVersion: 2.20.8-0ubuntu10
Architecture: amd64
BootLog: Error: [Errno 13] Permission denied: '/var/log/boot.log'
CompositorRunning: None
CurrentDesktop: ubuntu:GNOME
Date: Fri Mar 30 11:10:19 2018
DistUpgraded: Fresh install
DistroCodename: bionic
DistroVariant: ubuntu
DkmsStatus: virtualbox, 5.2.8, 4.15.0-12-generic, x86_64: installed
ExtraDebuggingInterest: Yes
GraphicsCard:
 Intel Corporation HD Graphics 620 [8086:5916] (rev 02) (prog-if 00 [VGA controller])
   Subsystem: Lenovo HD Graphics 620 [17aa:3801]
InstallationDate: Installed on 2018-03-15 (15 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180314)
Lsusb:
 Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
 Bus 001 Device 004: ID 0cf3:e300 Atheros Communications, Inc.
 Bus 001 Device 003: ID 138a:0094 Validity Sensors, Inc.
 Bus 001 Device 002: ID 5986:2104 Acer, Inc
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: LENOVO 80VF
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-12-generic.efi.signed root=UUID=0bf3fe9c-33ec-4653-b53e-adc64d7b62a0 ro quiet splash vt.handoff=1
SourcePackage: xorg
Symptom: display
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/31/2017
dmi.bios.vendor: LENOVO
dmi.bios.version: 2JCN39WW
dmi.board.asset.tag: NO Asset Tag
dmi.board.name: Agera
dmi.board.vendor: LENOVO
dmi.board.version: SDK0J40709 WIN
dmi.chassis.asset.tag: NO Asset Tag
dmi.chassis.type: 31
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Lenovo YOGA 910-13IKB
dmi.modalias: dmi:bvnLENOVO:bvr2JCN39WW:bd05/31/2017:svnLENOVO:pn80VF:pvrLenovoYOGA910-13IKB:rvnLENOVO:rnAgera:rvrSDK0J40709WIN:cvnLENOVO:ct31:cvrLenovoYOGA910-13IKB:
dmi.product.family: IDEAPAD
dmi.product.name: 80VF
dmi.product.version: Lenovo YOGA 910-13IKB
dmi.sys.vendor: LENOVO
version.compiz: compiz N/A
version.libdrm2: libdrm2 2.4.91-2
version.libgl1-mesa-dri: libgl1-mesa-dri 18.0.0~rc5-1ubuntu1
version.libgl1-mesa-glx: libgl1-mesa-glx 18.0.0~rc5-1ubuntu1
version.xserver-xorg-core: xserver-xorg-core 2:1.19.6-1ubuntu3
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:18.0.1-1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.99.917+git20171229-1
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:1.0.15-2