The website sucks because I had to do work to understand the problem.

HOWEVER, the bug is interesting.

I can't reproduce this bug, but I have a suspicion as to what it is. As pointed out in the linked video the hitbox for buttons changes size based on predicted next letters.

The hitboxes are dynamic based on the most likley next letter. But that changes depends on your typing style. For example my real name is similar but not the same to a common english name. however both auto correct and the dynmaic hitbox allows me to reliably type my name, now.

This took time, but when I recently got a new work phone, I had to train it to accept my name.

TLDR: I don't think its a bug, I think its a learnt behaviour based on your most common words.