It might need a browser reload to take effect.
It’s’s subtle, because it’s only locked while you are moving (and a short period after you stop).
This is so that once you start moving towards your choice, it doesn’t disappear from underneath you, but otherwise you get updates as fast as practically possible.
Yes, if we sorted old->new at the bottom, then newly appearing ones aren’t a problem. Actually, I suspect that’s how it was before. The lock solves the problem of older ones disappearing and everything “popping up” one or more entries.
Since they appear and disappear at the same rate (average over time) then you would have a problem whichever way you sort
You can prove to yourself that it is working by just gently continually twitching your mouse over the list. You should see the offers gradually having their buttons replaced by “cant accept”. When you stop moving your mouse (a second after) the list will update with the latest.