Fps Drop After Updating To 4.11 And A HUD Problem

Hello.
After updating my project to 4.11 i encountered two problems:
1.Major fps drop while next to a big group of destructible cubes (while walking towards them the fps starts to drop,without interacting with them.
2.While my HUD is displayed,and my editor is playing in full screen,i get a weird seam,at the left and at the top of my screen.

These problems wont occur at the previous version (4.10),and also,i have a high end gear,so i don’t believe its a hardware issue.
Thanks in advance.