Game version: 1.17
Mod version: 1.0.0
Fabric API version: 0.36.0

Steps to reproduce:

1. Craft 2 static walkways
2. Place them down together (like in the demo picture provided for the mod) above ground facing West or East

Expected result: the outside handrails remain and keep collision, inside handrails disappear and lose collision.

Actual result: the outside handrails remain and lose collision, inside handrails disappear and keep collision.

Edit: works as intended when placed on the ground.

Edit2: I finally figured the real factor, it depends on whether the walkway faces North/South or West/East. N/S Works as intended, W/E does not.