Hello 👋 @atzmael did you have any luck figuring this out? I, too, currently get this error every once in a while but only client-side 🤔

I get this stacktrace btw.:

Uncaught Error: ChangeTree: missing index for field "undefined"
    at e.assertValidIndex (index.js:388)
    at e.touch (index.js:268)
    at e.touchParents (index.js:278)
    at e.change (index.js:264)
    at e.set [as x] (index.js:1308)
    at e.decode (index.js:2570)
    at t.patch (NoneSerializer.ts:7)
    at e.patch (Room.ts:267)
    at e.onMessageCallback (Room.ts:252)