If you didn't, though, then that'd explain it partially: LT only syncs active users, that is, if you haven't logged in the last 7 days, LT will stop including you in the scheduled task that updates all wishlists & libraries.
Let me look at it again though...
Oh, right. Just as I feared, lol.
Auto-sync was launched for active users who had last auto-synced in the last 24 hours... That should obviously be the opposite, lol: active users who haven't been auto-synced in the last 24 hours.
Fixed that. Sorry about the mess. The issue was due to a frenetic copy & paste where I used the same code as the activity test, except it should have been reversed (since I was testing for non-sync state, rather than up-to-dateness. Is that even a word?)
The problem is, as the admin I'm obviously visiting the site every day. If I had for any reason been offline for 25 hours, then I'd be off the autosync list forever. Which would have suddenly made it obvious to me that it was buggy... Up until now it worked too well, so that explains why I had my library up to date every time I went back to the site after a trade, ahah...
Quick poll: should I use the auto-sync scheduled task to also remove items that went from your wishlist to your library..? Or maybe limit it to Steam wishlisted items that went to your library, since it's likely you would want those for yourself only. Of course, I'd exclude all games with a + (extra) tag... I never did it until now because I record these things and I tell users to remove their wishlisted items when they visit their wishlist.
Maybe I could make it a flag when I start overhauling the profile area... By default, remove wishlisted when found in library. If a checkbox is clicked, only ask for advice when visiting the wishlist area.
I'm also considering not syncing wishlist & library until the user started adding tradables... I've occasionally seen people register to the site, and then no longer come back to it, making LT import their wishlist & library for zero benefits (except artificially changing the H:W ratio for nothing.)