Hey QSBen,
Can you provide me with the VR device you are using when testing, as well as the material in question so I can accurately reproduce this issue on my end?
We tested this on a Vive in a new 4.13 blank VR project and was able to see the MaterialBillboard component in both eyes as expected. If it would be easier, we can get your test project and test that exactly.
Thank you,