Wandering Trader Llamas Despawn while on Lead

They fixed the persistent trader llamas, but now they will despawn while still on lead. 

 

To Reproduce:

Find Wandering Trader with at least one llama

Move far away (I went up to 200 blocks but this is probably unnecessary)

Move back to the trader

 

Expected:

Trader is still there with llama(s) on leads.

 

Actual:

Llama(s) is/are gone, lead floating on the ground. 

 

This could be the lead breaking, which causes the llama to despawn.