I think it's showing missing sleepers? HPL please confirm.
Missing sleepers yes, and some parts of the junction too (rails only have their top displayed). I noticed today there is the same issue in TRS19 Build 114800.
The ultra post-processing does have a new sharpen effect added (I'd missed that info). We'd like to hear your feedback on each of the post-processing settings.
It is perfect for me and has no impact on framerate (Ultra @2560x1440).