This issue applies to both heightmaps and normal maps when used alongside the following plane-shaped blocks:

rail_activator
rail_activator_powered
rail_detector
rail_detector_powered
rail_golden
rail_golden_powered
rail_normal
rail_normal_turned
glow_lichen
sculk_vein
double_plant_sunflower_front
double_plant_sunflower_back
resin_clump
And the following textures but only in specific cardinal directions:
big_dripleaf_top
big_dripleaf_side1
big_dripleaf_side2

Steps to re-produce:
Create PBR texture-sets for any of the blocks from the list above and observe their heightmaps and normal maps in-game.

Additional Notes:

• To further explain on the images, I initially assumed the issue occurred because the planes/model for this block is unintentionally flipped.
  Upon closer examination by placing resin clumps underneath an invisible block such as barrier block, it appears the texture is inverted on not just one but both sides.

• This issue is not exclusive to ray tracing and applies to Deferred Lighting technical preview as well, which means it is present in vanilla game too, but is only exposed with the use of heightmaps or normal maps on the texture, given it happens only to some plane-shaped blocks, and other plane-shaped blocks outside of the list above do not exhibit this issue.