The Bug:

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.

Video:

https://youtu.be/Vhkui-Vnf34

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)