Hello,
I’ve got this warning repeatedly today. (I’ve successfully restored my TW but I will definitely start back up versions from now on.) A quick search in text tells me this function is defined in the shuffle plugin by mklauber.
This plugin worked well until today. I did some test, and it seems like I couldn’t put a shuffle operator in Default tiddlers filter.
I have no knowledge of javascript so I’m afraid my experiment stopped here. I’d like to share my experience with the community in case someone else need this info.