At least some such cameras were limited to less than 30 minutes, because EU tariffs classified something that could record for more than 30 minutes as a video camera, which had a higher import duty. Source: https://www.borrowlenses.com/blog/video-recording-limits-in-...
Having the camera overheat seems like a clumsy way to do it, though. The time limit would depend on ambient temperature and manufacturing variance in the heat sink.
This limitation applies to my Sony A6000 too, thankfully there is a software hack to unlock an unlimited recording time.