Interesting. If they really have stopped marking the playfields, this might mean that JJP is indeed planning to change vendors eventually. I doubt they want people to be able to identify exactly which games have a new playfield vendor and which games don't. They might even keep installing washers for a while, even after there is no longer a need. They'll probably try to keep it secret at least until the old playfield inventory has been purged from the factory/JJP and passed on to the buyers and distributors. Once the cat is out of the bag, people will zero in on a build date for games with the new playfields and games before that date will be less desirable immediately.
Of course, this is assuming the new vendor will be an improvement over Mirco! Over the last three years, this problem has been rumored to be fixed many times only for it to come back again. The only way to be sure is to wait and see. I just got a Jurassic Park Premium with April 2021 build date and the clear is beautiful with no pooling. I held off buying when they originally came out because of the issues.