WebKitNetworkProcess is grabbing serial port

At random times the serial/tty port to my Arduino (teensy 3.2) is being opened by WebKitNetworkProcess and not being released.

Ubuntu 18.04.1 LTS
libwebkit2gtk-4.0-37: Installed: 2.22.2-0ubuntu0.18.04.2

expected to be able to open/access the tty associated with my Arduino
got blocked because it's open by WebKitNetworkProcess

The arduino implements a USB serial device. Unplugging the cable and plogging it in again causes a new device name to be assigned since the one held by WebKitNetworkProcess is still in use.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: libwebkit2gtk-4.0-37:amd64 2.22.2-0ubuntu0.18.04.2
ProcVersionSignature: Ubuntu 4.15.0-36.39-generic 4.15.18
Uname: Linux 4.15.0-36-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.4
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Mon Oct 15 15:41:30 2018
EcryptfsInUse: Yes
InstallationDate: Installed on 2018-01-30 (257 days ago)
InstallationMedia: Ubuntu 16.04.3 LTS "Xenial Xerus" - Release amd64 (20170801)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: webkit2gtk
UpgradeStatus: Upgraded to bionic on 2018-07-11 (96 days ago)