If the user upgrade title wraps in the User Upgrades list, it causes some white space above and below the 'Downgrade' button. I guess this is more of a styling issue than a bug, but I wasn't sure where else to post it.
Indeed, this does come up every so often. It generally doesn't come up on "common" pages, as we don't use tables particularly frequently.
It's mostly a side effect of a non-ideal approach to adding this link. There is an advantage relating to getting the exact width we want, but it comes with this. It's not something I'd see really changing in 1.x, but it could be something at a 2.x level (if the other trade off is worthwhile).