Basically, hover texts of advancements show up on wrong places. Refer to the screenshot taken. This bug is like
MC-117318 but on a later version.
After a little bit of observation, it seems like the the hover texts detects the cursor upside down. It's really weird and I have no idea why this happened. (If you're a bit confused, check the second, third, and fourth screenshots.)
MC-121419 Click and hover events are offset in chat