While using both Universal Graves and Fabric Tailor in the server, changing your current skin changes the skin displayed on graves (as expected), but upon running /skin clear all graves featuring your player skin will default to steve, and further graves created appear with steve as the icon until you leave and rejoin the server.

In the first picture I died, and in the second one I cleared up my current skin, which uses the one bound to my account (it was already my default, but /skin clear makes the grave become steve). Then after leaving and rejoining the server and then dying, a new grave is properly made.

Leaving and rejoining fixes and future graves but it also seems like it causes any existing graves to disconnect from the player, because as you can see in the following picture there's steve graves mixed with my skin and another skin I just changed to using Fabric Tailor. I left and rejoined and the graves with my skin (the purple ones) weren't changed and the ones created under the newest join session changed with fabric tailor without issues.

Steps to reproduce the steve issue:

1. Die and create a grave
2. Run /skin clear (make sure you have the Fabric Tailor mod in your client/server)
3. Your newly created grave is now steve. Dying again will only create steve graves.
4. Leaving and rejoining will fix the problem for future graves and they will use your skin. Old graves remain "unlinked".

Originally reported in samolego/FabricTailor#67

Since a lot of things changed since then, I'm closing it as it might be fixed. If not, it's more of an issue with FabricTailor