I am having this issue as well- I've noticed that the counter seems to reset when I switch households. So when the sim first steals the loot, it shows up in the ltw panel as being counted, but if I switch households and then switch back the counter is set back to zero. When I look in the family inventory at that point the stolen items are still there, and they're counted as stolen, but it no longer says where they were stolen from. Instead it says something like "big cow sign, stolen from" with no victim listed.
ETA: My sims never travel.
Hey, you know that little warning popup that goes "WARNING! SWITCHING HOUSEHOLDS WILL RESET ALL OF YOUR WISHES! ARE YOU SURE YOU WANT TO DO THIS?" Have you tried reading that?
That's not what that means. It means all the current wishes, not your progress toward your LTW. I've changed households many times without it affecting progress toward LTW. Shouldn't matter anyway...if the "stolen" tag wasn't bugged, then none of that would matter because your progress would still be the same as long as you still owned the items, and there's nothing saying "WARNING! SWITCHING HOUSEHOLDS WILL CAUSE YOU TO LOSE ALL YOUR SHIT!"