To reproduce:

1. Open new project.
2. Set Project Settings -> Editor -> Version control mode to Hidden meta files
3. Enable collab.
4. Look at Version control mode, value remains the same (hidden)

[optional]
5. Disable collab
6. Set Project Settings -> Editor -> Version control mode to Visible meta files
7. Enable collab.
8. Look at Version control mode, value remains the same (Visible meta files) (and in explorer they are visible)

Actual result: Version control mode remains the same after enabling collab, but selection field becomes disabled
Expected result: Version control mode should be forced to visible meta files (if it's actually necessary) OR Collab seemed to work fine with both visible and invisible meta files., if so, guess this option should be always available, no matter if collab is used or not (maybe user doesn't want to see meta files in explorer even when using collab)

Reproduced on: 2017.3.0a1