iMac graphics bug and bluetooth not connecting

Hello all, I am running Zwift on an mid 2011 iMac with an i7, 8gb ram, and an AMD HD 6970 and I am getting an in game graphics bug that looks like a pixelated shadow that is in front of my avatar. ![Screen Shot 2021-11-21 at 9.09.38 PM|690x388](upload://zssEJz6VmONmS9j

Does anyone have any suggestions on what is happening and how to fix it?
Also, the iMac doesn’t see my Wahoo Kickr Core in bluetooth only with an ANT+ sensor, any suggestions with this problem would be appreciated.

Looks like this is back: Black ‘Refracting’ line on the road

Thanks for the link.