1.16.3, 1.16.4 Pre-release 2, 1.16.4, 20w48a, 20w49a, 20w51a, 21w03a, 1.16.5, 21w05b, 21w06a, 21w08b, 21w15a, 1.18.1
A cat can teleport off a lead after giving a gift in the morning. This is due to the teleport assigned to the cat after giving gifts. The teleport radius is around 5 blocks, so if the cat is already far from the lead and it then teleports, it can travel far enough to which it will break the lead.
Steps to reproduce:
1) Create a world and tame two cats.
2) Place the cats on leads and attach them to a fence.
3) Place a bed around 8-9 blocks from the fence post.
4) Sleep at night in the bed.
5) A cat can teleport off the lead (this is a low chance due to the random teleport radius, may take 5 or more times)