I landed on that the problem was caused by me playing rotationally. The freezing sim might have been freezing the last time he appeared on a lot I played, it might very well have been Winder, because I stop by each house only every 2nd year. It's had to even imagine what they might be up to while I'm not watching...
In this particular situation another household member was wearing her bikini, and not freezing at all. Which should suggest that their status was pre-individual rather than based on current environment. Which again makes the game pretty unlogical. I wish all that stuff would be based on current lot, and not on what they were up to "ages ago".
