Zwift did ‘sort’ this out in December but I believe things have reverted back to how they were pre 1.55.
Easiest way to identify changes is to watch race videos.
Pre December and now are the same - race results from the gun and HUD from crossing the start line (not the pen line). At end of race HUD time doesn’t change.
Feb/March videos - race results from the gun, HUD time from the gun. At end of race HUD time changes back to the ‘from crossing the line’ time.