Mobs in village prior to raid count towards a raid once one starts

If a mob that is used in raid waves is present in a village once a raid begins, they count towards the raid's progress. Some people decorate their bases with mobs, and they would have to kill them in order for the waves to progress. I would imagine a fix would be to have raids only register mobs with a special nbt tag towards waves. Shouldn't be too tricky of a fix.