I‘m aware of the current federation issues that might also be the reason for this issue but I noticed that while federation of posts from feddit.de works sometimes as well as posts and comments from other instances no comments from feddit.de are syncronised at all.
It might be better to ask there but as I do not have an account there I thougt I first ask here if this is already known. Does somebody else also have this problem?
This indicates to me that the 0.19.1 bugfix did not catch all cases and there are still issues with federating of comments and votes.