I faced this bug in Ubuntu 18.04. When I used Alt + Shift + 7 inside Webstorm which is the command for Find Usages, it actually changed the language because the command included Alt + Shift (I previously set this by using Gnome Tweak Tool). Here is a bug related to this in Launchpad.
To fix this you need to execute the following commands:
sudo add-apt-repository ppa:nrbrtx/xorg-hotkeys sudo apt-get update sudo apt-get dist-upgrade
and then restart your laptop. This works, but sadly now, whenever you use Alt + Shift + 7, it will search for usages and then change the language.