I made a post from my AZ account in !vamp_tm@ttrpg.network and left a comment under it.
https://aussie.zone/post/35026266
The post seems to have federated fine.
https://ttrpg.network/post/40584555
But the comment did not.
Along with my previous two posts about federation issues with quokk.au, the common factor seems to be AZ, so I suspect that is where the issues stem from.
Where do you get those graphs? Does it also compare federation between Lemmy and Piefed/Pylova instances? I’ve noticed at least some of my comments on Quokkau are having federation issues with AZ.