Bug with timed practice
I currently have over 23 million minutes due to a bug. If you click on "don't know the answer? - skip" button and then click on "continue" or press enter a few times in quick succession (I'll call this a "cycle"), then the timer bugs. I don't have a screenshot (I'm horrible with computers and have no idea how to add one here), but I'm sure it be replicated by anyone. If others could check it out and confirm, that would be helpful.
I just tried it again and it took around 15 cycles. So when trying to replicate it, keep in mind that it might take some time.