Any time a tile isn’t filled in you will get an error. Sometimes the missing tiles shows that way for everyone because of a problem with the image provider, but we know from previous times that even though me or Dave can see the tiles, you need not see them.
If you still have 2018 around it would be interesting to see if that is missing the same tiles. 2018 and 2019 have different folders for caching, if both fail it’s more likely to be a network issue.
Try going back to a lower zoom, then 18X again, and see if that is enough for the tiles to fill in.