1.I moved my data folder to a separate drive, intending to get a clean install, for Requiem.
2.I uninstalled Skyrim via steam, leaving SKSE and Dragonscript in the route folder.
3. I reinstalled Skyrim via steam.
4. When going to install Requiem, my Nexus Mod Manager, had retained the data folder files, contracted to my old Skyrim.
5. I scratched my head, and said forget requiem.
6. Without moving my other folder back in place, Old Skyrim saves and mods all worked regularly.
7. Dragon encounter on a clean save, has the mesh all blobbed out. a bit of an edge line here and there, but really, just a blob of melty clay.
8. My game didnt have this issue before this.

Any suggestions, I am going to verify integrity now. see what happens.

SO you arent using requiem now but you loaded a save that used requiem? Or did you start a new game?

This sounds like a texture/mesh problem. Does the dragon look purple? You mentioned not restoring the old data folder. Did you reinstall all your mods from NMM?