Weird glitch with camera in build if coming from another scene

FMStudio

Hi Chris, I'm having a very weird issue with camera against which I'm struggling for days without any luck.
Basically it looks like camera is rapidly shaking around when moving and a kind of flash is shown. It's pretty hard to explain so I've made a short video for you:

you can see clearly at 00:03 this flash (check that the video is playing in HD otherwise, being really a very few frames, you may miss it).

These are the very strange things about this glitch:

• it only happens in build, not in the editor. Every platform (iOS, Android and WebGL)
• found out it also happens in the Editor if you switch to a different scene and go back to the game one. The new info I got from being able to replicate the issue in the editor is that the camera doesn't seem to move (transforms don't show crazy values when the flash is shown)
• if I start the game in this specific scene, everything runs smooth as expected, but if I add any other scene before (i.e. a splash screen, or a main menu scene...) then switch to this one or start here then switch to another scene and back here, it alway happens

I tried lowering the timestep to 0.01 from 0.02 and played with a lot of settings but always with no luck.

Any idea on what can I do? Having the whole game in one single scene is not an option as it would become too heavy to handle.
I'm on Unity 2021.3.20f1 and AC v1.75.1 (tried upgrading to the latest version but the glitch was still there and other things got broken so I decided to stick with the old version)
Happy to share any other setting you may need.
Thanks a lot in advance.

FMStudio

Having the chance to replicate the issue in the Editor made us solve the issue.
If anyone is interested, it was due to Third Person camera being a child of the Player. So when moving rapidly it kind of stayed behind for a frame.
Still don't know why it happened only after switching/refreshing the scene but unparenting them fixed totally.