Is there a maximum number of labels? We can't move new labels around.

Is there a maximum number of labels? We can't move new labels around.

Paying business client here. One of our employees has a lot of labels (100+) and they are all necessary. But, lately we've found that newer labels he creates cannot be moved/sorted. If he is able to, the new labels jump back to their pre-move positions (the place they were when the labels were created). Any idea what would cause this? Thanks!