So we succeed in repro the issue. We recently used more multi-threaded code during the light baking, and we discovered an edge case in our job system. We’re working on a fix right now, hope you could get a public release next week.
In the meantime, as a work around, you could disable “Use job threads” option in Preferences/Jobs as suggested by @Chris_CTD . It shouldn’t slow down baking too much if you’re using the GPU lightmapper.