So this is an issue that is still on our Mac Support team’s radar. I’d recommend watching the Mac Support Forum for more information. This thread, in particular, as they are the ones working with Apple to resolve the issue. https://us.forums.blizzard.com/en/heroes/t/visual-bugs-since-latest-patch/26789/124
Here is a good post from that thread outlining the situation from our Mac Support blues.
Thanks for your continued reports, and sorry about the silence on this thread. This is still on our radar and we have not forgotten about this issue. Our team is in communication with Apple regarding the issue. There are some requirements that are reliant on other factors that are outside of our control. It’s an immensely frustrating issue and understandably so, but there is no time frame for this yet, since our team wants to ensure everything is set in order rather than have something come up resulting in delays.
We want this fixed for everyone and would prefer that no workarounds are needed just to be able to play the game. Once we have word on solid changes and a full resolution, we will let you know so that this can be retested so that we can ensure all systems are up to scale.
While, we may not post every time here, we do read through each of your reports! I greatly appreciate your patience and we’ll post when a new update is available!
And there is another suggesting that setting Shaders to Medium, might help alleviate some of this issue as a temporary workaround, which might help you in the mean time.