I have noticed this a few times, sometimes it happens sometimes not. I do not understand what triggers it, but crouching fixes it. I tried to search if its a bug already listed but could not find it, but I apologise if it is already listed.

The character behaves like they are suffocating in the wall above, this also happens when swimming in 1x1 and you can accidentally get up but usually this would hurt but it does not make you take any damage, the same with in the video example.

My FOV is 90 not sure if that matters.

The server is 1.17.10.04, on Windows 10. 
No mods, just vanilla install.
Experiments active on the server CnC

It may be of help that I converted the world this is a copy of my world that the game made to enable the CnC.