When I try to move the mouse pointer or barely touch the trackpoint, the mouse pointer jumps to the edge of the screen.

Specifically:
- Pushing the trackpoint mostly horizontally, left or right, makes the pointer snap to the left edge, at the same height
- Pushing it mostly vertically, up or down, makes it snap to the top edge of the screen
- Pushing diagonally makes the pointer, as you might've guessed, jump to the top left corner
- After the initial jump the trackpoint works (I just have to move the pointer back to where I want it), then the problem reoccurs after the trackpoint is unused for a few seconds

Laptop:
- Lenovo Yoga L380 13.3" with HD touch screen
OS:
- KDE neon 5.14
- KDE Plasma version 5.14.0
- KDE frameworks version 5.51.0
- Kernel 4.15.0-36-generic

This seems to have begun happening after I tried using a Corsair Gaming M65 Pro RGB FSP mouse as I don't remember this happening before. At first, using the mouse with the laptop exhibited this behaviour and I gave up using it to resolve it later, then I discovered that it had begun affecting the trackpoint on the keyboard too.

Touch pad is unaffected.

Logging out and logging in with desktop session choice of "Plasma (Wayland)" instead of plain "Plasma" seems to make it go away and the trackpoint behaves normally.
The login screen is not affected, but the lock screen is (except for in wayland session).
Rebooting does not help.

Result from $ xinput list without wayland:

⎡ Virtual core pointer id=2 [master pointer (3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)]
⎜ ↳ Wacom Pen and multitouch sensor Finger touch id=10 [slave pointer (2)]
⎜ ↳ Wacom Pen and multitouch sensor Pen stylus id=11 [slave pointer (2)]
⎜ ↳ ETPS/2 Elantech Touchpad id=13 [slave pointer (2)]
⎜ ↳ ETPS/2 Elantech TrackPoint id=14 [slave pointer (2)]
⎜ ↳ Wacom Pen and multitouch sensor Pen eraser id=16 [slave pointer (2)]

I've switched to wayland until I figure out a way to fix this, although the compositor presents glitches in window shadow halos.

⎡ Virtual core pointer id=2 [master pointer (3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)]
⎜ ↳ xwayland-pointer:6 id=6 [slave pointer (2)]
⎜ ↳ xwayland-relative-pointer:6 id=7 [slave pointer (2)]
⎜ ↳ xwayland-touch:6 id=9 [slave pointer (2)]