There's been a few days since I encountered an error with my wiki (lakehub.ga), and I've seen also someone complaining about this on the Discord server.
It seems like the issue is caused by the skin Chameleo, because if you try to ?useskin= with another skin the issue goes away. However I'm not really sure why it's causing this, as it doesn't offer any detail. It's also not consistent, because my other wiki that also uses Chameleon is not having this issue (koopacabanawiki).