I noticed my error analytics was full of errors and managed to get some of it to show up in studio for the first time ever.
There is a random chance of localscripts which were created on the clientside not being disconnected properly when the parent is destroye on the serverside.
Oh the parent is destroyed, by the server - got it.
That should disconnect, although it could be related to a reference being held? I know parenting localscripts to nil used to be a way to avoid having exploiters delete them - not sure how much of that is still around.