At some point in the development of the stereoscopic rendering, the "One button look" angle setting became doubled, so that, for example, when set to 45 degrees your view will turn 90 degrees instead.
Narrowed it down a bit. Seems to be related to having NPClient.dll in place (I've been using FaceTrackNoIR and Opentrack) regardless of whether headtracking is running.
If I move that DLL out the way then LFS is working as expected.
I'm aware that pressing both doubles -- weird effect with this is that (90 + 90) * 2 = 360... I feel like an owl
Thanks. That led me to the answer. The same bug can be reproduced without NPClient.dll - using Axis Look and assigning an Axis. Then the same "double one button look" bug appears. I've fixed it in both cases and tested it in the Axis case. To save me installing TrackIR, please can you check the fix when Test Patch K4 is released?
EDIT: The same bug also existed in Look functions "ms X" and "ms XY".