The left menu button on Oculus Touch doesn't have it's input received when it is assigned to an action mapping. This looks like it stopped working after SteamVR was integrated into the engine.
Found in 4.24.3 CL#11590370
Reproduced in 4.25.0 Preview 1 CL#11723679, 4.26.0 CL#12052394
1. Create a VR Template project.
2. Add an Action Mapping (OculusLMenu) that uses the left oculus menu button.
3. Print out a string when OculusLMenu is pressed.
Results: The left menu button's input isn't received.
Expected: The left menu button's input is received.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-90310 in the post.