So I was going through Scratch, and on this account: https://scratch.mit.edu/users/BeastAnimator/ the comment on the account showed 4 years ago, but the account age was 3 years and 11 months!?!? Then the account that commented on the alt was made 3 years and 12 months ago! Not 4 years!!!

There is no bug: Scratch rounds the time since a user joined or since a comment was posted, and the rounding for user join dates is more precise than the rounding for comment dates. If you hover the mouse over the “4 years ago” or “3 years and 11 months”, it says the exact day that they were made, May 26 2020, revealing they are both from the same day. The account that commented was made May 20 2020.