Can confirm I saw the same issues with random black boxes popping up on Canopies and Coastline today. Also when on the new coastal road the rider boxes for riders behind you at the bottom of the screen randomly turned black and stretched out a bit.
Running Zwift on a Mac, haven’t seen the boxes and did that route yesterday, but there are a couple gaps in the ‘road’. Just a couple though, so great job. The varied scenery is so busy, maybe this boxes are a caching issue? The Crab Shack sign is hysterical and amazing! Good call putting that in. The New England area is so iconic, interesting, amazing.
I’m not sure if this is related or not but there also appear to be large black squares on certain rider names when they are closing in on you. Potentially a text / emoji creating a larger background for the name than normal… or another black square issue.