None of the suggestions worked for me when this issue occured. I'm not sure what causes it, as it doesn't always happen for me, but it's very annoying when it does and makes the game unplayable.

So, inspired by Dual Monitor Tools I wrote a small application to constrain the cursor to the monitor of the active window (assumes you're playing fullscreen - I could've kept it to just the window but since I play fullscreen this makes it easier to access the taskbar afterwards). Perhaps it's useful to others searching for a workaround until it is properly fixed:

https://github.com/MvRens/MouseTrap