Hi! I've been running a modpack on a server for my friends for about a week now and we noticed that when we try to put our dogs on our heads, they visually appear to be on our backs instead, and right-clicking them off is impossible. After some testing, I was able to confirm it's an issue with the Piggybacks mod. I've already filed an issue about the conflict on Piggybacks' Github here with more detail, but here's a basic rundown:
Minecraft version: 1.21.1
Fabric version: 0.17.3
DTN version: 1.18.54
Other mods: While the modpack has a great deal of other mods, I was able to confirm it happens with only the following: DTN, Fabric API, Forge Config API Port, Faewulf's Lib, and Piggybacks itself. (Faewulf's Lib is required for Piggybacks.)
We can get our dogs off of ourselves by relogging, so it's not a catastrophic issue, but it is kinda annoying. Thanks for the awesome mod, I hope you have the time to take a look at this issue soon.

Hmmmm..... This seems like mostly out of our control since Piggyback might have overridden the mob's placement when riding.
You might want to ask them if they have a config to blacklist certain entities from having their riding position being overridden.
Although let me see what I can do on DTN side meanwhile.

Thankfully, Piggybacks' dev has already responded and stated they are working on an update. They specifically said that DTN probably won't have to do anything. I'll close this issue once they've pushed out the update.