Light code looks to be "inverted". When you look at the side of the code - you can clearly see stuff on the other side of the code. But when you look where cone is targeted at - it's darker.
ImmersiveVehicles 1.20.10-22.17.0
OCP 1.20 beta 1.1

Screenshots on IV-only modpack:

More screenshots but on a modpack with Embeddium and TrueDarkness mod:

Don't report beta bugs on the GitHub. Report them on the Discord where you got the beta from.

Also, this is per-design and a limitation of the MTS lighting system. So not a bug to begin with.