Some strange visual bug appeared on every non-system app's windows

Some strange transparent blurry strip appeared at the bottom of non-system app. Need help. How to remove these? Thank you!

PS: It’s also visible at full screen, little bit annoying

Found out that is the problem of the Pocillo theme. Is there any way to fix it?

thx for the report. This has now been fixed - the update will be available in the next few hours.

Can confirm. Problem has been fixed THANK YOU!