There are issues on 20m FT8 -- more than just the time sync.
I noticed that they do not TX all the time. There are periods they will skip every other of their TX cycles. When they resume, the same calls are still being serviced for the most part.
They TX mostly with 5 streams, the third stream is almost exactly on 1000Hz. So 2 streams under and 2 streams above 1000Hz. That must cause problems with the F&H standard.
There were times when the streams seemed to shift around 400Hz lower. I cannot say for sure it was their signal because I had no decodes of those, but it coincided with when they were supposed to be on TX and were not on the expected frequency.
The above could all be happening on my end, who knows. Just mentioning them in case others noticed something similar.