This is what I told Jack too, this watchmaker may of not ensured the gasket was securely seated, and its come off as he was pressing the bezel assembly onto the watch, this this gasket is not causing the gap one side.
Funny you should mention this, I did reply to you next door about some TC subs having a white paper very thin spacer on the movement ring. I have just been working on another TC sub, and it has both a white ring on the movement holder, AND a dial spacer, its the first time I have seen this..
White paper ring..
Dial spacer..
Looks like your problem maybe sourcing the actual Date Wheel Overlay. I can't see the teeth in the above photo which could indicate its an overlay.
What movement does your watch have?
Day Date maybe?
Your watchmaker losing small, tiny parts is one thing, but to lose to key components rings alarm bells.
Change your watchmaker is my advice!
To me, TD's although given a Trusted status, their websites info has a lot of lies, but these are being blamed on the factories given the TD false info.
High beat 21J being misreported as a 2836-2
Sapphire Crystals when normal glass