The wipers on the GWE HST don't seem to have any effect when turned on. The accumulated rain (in the rain storm weather setting) doesn't disappear, but switching to external view will clear it.
I got this bug today when playing a service with dynamic weather on. It started raining and the rain made odd patterns on the screen and was not wiped away. PS5.
That was introduced with the last TSW3 patch, which added Livery Designer compatibility to the GWE HST and broke it. Was reported, but no feedback from DTG. You'll need TSW4 to have it fixed I suppose (or revert GWE to the pre-patched version using Steam console)
