When using instance stereo with custom stencils, they do not render as expected. It appears to render the stencil in one eye at a time (as the user's head is turned).
Regression: Yes This was working in 4.21.2-4753647+++UE4+Release-4.21
Result: The stencil renders in one eye at a time
Expected: The stencil in the case of this test case would appear as one 3D cube and would render in both eyes while looking at the object with the stencil applied
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-72496 in the post.