Problem with flickering mouse - Link to affected project included 19MB

[inedible.red]

I’m breaking my head trying to fix this little visual bug. The mouse flicker when replaced by a UMG widget and set invisible like so:

[Album] imgur.com

and

This is a little project I’ve made with the problem:
https://drive.google.com/open?id=1bbpJrAUV9CtqiWYbSlEH3QoGV4wQpQsD