Steps to Reproduce (Creative mode):

1. Have any items in the inventory
2. Grab a bundle from the equipment tab and try to use it immediately

Steps to Reproduce (Survival mode):

1. Have any items in the inventory
2. Use leather and string to craft a bundle
3. Grab the bundle from the output slot and try to use it immediately

Observed Results:
The fail sound is played and the bundle can't be used without placing it in another slot first.

Expected Results:
The bundle works right from the start.

Notes: It also can't be placed inside of other bundles and doesn't show any detailed information in its tooltip, so it's likely that the "minecraft:storage_item" component doesn't load initially.