Yep, so I'm having the same error. I did notice another problem before I got this error, though, so in case they're related, here's what happened:
I had my teen sim who was trying to get a scouting badge go for a series of jogs. I tried to have her jog long enough to get badge progress, cancel it, then have another jog action queued up. I was also viewing her badge progress intermittently to make sure it was progressing. This was in Del Sol Valley, and she lived in the Bailey-Moon house (she's Thorne's daughter with another sim I made - second gen ftw!). She didn't have a fitness skill before, so she quickly got fatigued. I tried to have her cast Scruberoo on herself since her hygiene was super low, and was making her uncomfortable. It didn't work for some reason (maybe she was too uncomfortable to cast it? is that a thing?), and so I decided to send her home since she was standing out in the neighborhood somewhere. She wouldn't route back there when I clicked on the little "go home" icon, so I found her house and clicked on a spot and told her to go there. She finally went. At this point I noticed that she had two negative moodlets that had moving downward arrows on them, as if something she was doing was helping to resolve them faster.
But they didn't go away, and they didn't even have a duration listed on them. One was for a pulled muscle, and I'm pretty sure one was that she was exhausted, both from all the jogging. (I was able to get her to cast Scruberoo on herself successfully after I cheated to make her happy, which didn't remove the moodlets, but buried them for a short time.) I tried resetting her with the cheat box, and through the debugging option from clicking on the sim, and neither worked to remove the moodlets. Finally, frustrated, I tried sending her to another lot (Ward Park) to see if that would fix it. And that's when the error happened. And then when I relaunched the game and tried to load that household, it didn't work. It looks like my old saves still work, and luckily I had last saved only (but, not really "only") an hour previously, so I went ahead and backed up my saves to be safe going forward. I'm not sure how the stuck moodlets could be related to this error, but since they happened one right after the other, I can't help but wonder.
I don't play with any mods.
Edit: I went back to my last save and kept playing. I encountered the same problem after I used "Modify in CAS" on my sunbathing sim. So this appears to me to be an error that happens after a loading screen, not just with travel.
