I think I know what they’re talking about. The Dragonflight reknown button has disappeared for all characters <70. Which means noone under 70 can access dragon riding talents. Also, you have to be 70 to use the rostrum so now the quest for that can’t be completed. There are a bunch of posts in bug reports…apparently for some people it’s affecting dragon riding too (though I am able to access dragon riding on all my alts between 64 and 70). 64 is my lowest level character though so YMMV…it looks like starting Dragonflight on a new character is an issue.
I recommend adding to these threads.