I dont know if this could be described as a bug. All I know that the following problem was not there before in previous Anki releases:
Pressing Ctrl + Z, for example during reviewing, returns the previous card as usual showing the tooltip Answer Card undone. However, I am unable to press Ctrl + Z again until the tooltip is gone.
During this time the window running Anki goes out of Focus and I have to click on the window again to bring it into focus again so that the Ctrl + Z shortcut could work again. Back then I was able to press Ctrl + Z multiple times without any lag time in between due to the presence of the tooltip or due to the window for some reason going out of focus. So this problem becomes much more noticeable if I click on Ctrl + Z repetitively.
I tried running Anki to see if this is due to some addon I am running and it was to no avail. The problem persists.