Arrows not stacking

Arrows collected did not stack 

What I expected to happen was...:
The arrows should stack in a stack of 64 

What actually happened was...:
5 arrows didn't stack with the other 11 arrows

Steps to Reproduce:
1. arrows collected in a earlier versions put 5 in one chest 11 in other chest 
2. taken out of a different chest in 1.20.5 release candidate 1
3.  did not stack