These performable actions (in both places; input bindings, and the 'perform action' code) rotate_camera_left & rotate_camera_right, revert to their hardcoded default input binding when the "Allow Rotation:"'s "Type:" is set to "Locked at 90-degree intervals".
This means, only shift+left & shift+right cause the camera to rotate when set to 90ºs.
Replication:
- Launch Steam Version. (files were valid, so no issue seen there)
- Create a New Game. (found this issue in my populated Blank Project, and a new Bare Bones Project)
- change the "Allow Rotation:"'s "Type:" to "Locked at 90-degree intervals", & ALSO (re)bind two other keys either through "Input Bindings" or manually through scripts to rotate_camera_left & rotate_camera_right respectively.
Note: 'Quickplay'ing before the rotation is set to 90ºs, and after 90ºs, will reproduce this 100% of the time for me, back and forth without fail.
Edit: using V1.1.7