Many working displays and many working systems. This is not a problem on my end.
The reason I asked the question is because it appears that the displays may be functional but that some recent small change in the I2C clock timing or some other small tweak is making them difficult to talk to. I'm even suspicious of my connector/header. So I've swapped 4 of my older displays and they all work. It's just this new batch (from two vendors) in the last month that have problems.