First-person attachables' scale & position is inconsistent across world/game reloads

Partner Rank: 3 - Normal
 
Verification Builds: Stable 1.21.23 & Preview 1.20.60.23
 
Regression Builds: 1.16.100
 
Summary: First-person attachables' scale & position is inconsistent across world/game reloads
 
Affects currently Live Content: No
 
Impact: We are using custom items to control the player's inventory as a core mechanic in our redstone-based game. This means the product will be launched where fundamental visual content is not consistent for the end-user experience.
 
Repro Steps:
1. Download & install the world sent to Greg Walls via Compass
2. Repeatedly load & leave the world / Repeatedly load the world & close the game
3. Notice that sometimes the attachables are correct, and most of the time they are incorrect (small and in a different position)

4. UPDATE; I've been getting consistent behaviour for the broken attachable now; where its correct on world load. The moment I press escape, it breaks. Reloading the world corrects it again. Please see the attached video.

Repro Rate:
~90% (intended attachables appear ~10% of the time)
UPDATE; It seems to be correct on world load 100% of the time; and pressing escape breaks it 100% of the time
 
Observed Results: The attachables change position and become smaller than intended most of the time
 
Expected Results: The attachables stay in their intended position & size across world/game reloads all the time
 
Screenshots/Videos attached: Yes, sent to Greg Walls via Compass
 

Notes:

• I am unable to determine whether this happens across game reloads or world reloads specifically. I have just witnessed it across game reloads so far.
• Added updated observed results for 1.21.23