Steps to Reproduce:

1. Enable the Bundles experiment
2. Grab any item and put it in the offhand slot
3. Grab a bundle and put it in the main hand
4. Switch to third person and empty it (due to MC-276336, items are not necessary)

Observed Results:
The offhand is lowered.

Expected Results:
The offhand stays slightly raised.

Screenshots/Videos attached: Yes

Notes: Other instances of the arm swing animation don't seem to be affected.