[jurialmunkey]

Clearing kodi cache will do nothing - it's not cached to disk. I just meant that kodi caches the last used directory in memory so sometimes going back and then reopening the same folder won't refresh the listing.

I don't cache anything for the list of lists and as you note, newly liked lists are showing immediately which demonstrates that I don't cache it (otherwise it wouldn't update at all)

However Trakt api server does cache things. There is nothing I can do about that. That's just how their server works - it caches some regularly requested user endpoints that aren't critical so it can serve the request faster.

Hey Jurial, thanks for replying and explaining everything. I know this must be the least favorite part of these projects (having to explain things to end users!

It's been about a week, and the changes I made aren't updated.  I wonder how long Trakt caches this stuff to Cloudflare?  Reading the links you gave, it looks like it's by design to reduce the API hits.  
And they (Trakt) don't seem to have the ability to do anything about this cache, if I am understanding the responses on those links, correctly?

You're understanding correctly but that's definitely far too long for it to be cached. It really should only be about a day tops.

Something funky is definitely going on with their API results for liked lists. I tested liking a few on the website and they will show up immediately in the API results, but unliked lists will persist in the results returned.