I don't have a diagnosis for arthritis, but I'm testing around a lot and maybe this info helps you in your journey:
I make gelatine from pig's feet occasionally, when I make it with just salt and some lemon or vinegar, I don't have problems.
Last time I thought, maybe try bell pepper, haven't tried for a while and I seem to do okay with capsaicin. Boy was I wrong, within a week I got horrible joint pain in the feet.
Bell peppers are seemingly high in lectin and other phyto-nutrients.
I recently found on hacker news, that I can neutralize oxolates with a pro-biotic - will try that for lectins next. Have to prepare the gut with L-Glutamine and Silicea.
God's speed!
Edit: Between ingestion and symptoms, it takes about 3-4 days
Very interesting. Have you tried consuming beef liver to see if that helps? I was able to completely stop my VitD supplements after consuming liver.