@cranewest thanks for the information.
Sorry, but maybe we were talking about different bugs.
The bug we consider that is fixed (according to our tests) is related to the UI, where the checkbox to expire posts was always enabled.
If you see posts that are expiring automatically without touching the post, that is probably caused by cron events that are still scheduled for those posts. Maybe that is a leftover of an old bug. We fixed the UI, but the cron events we can’t fix automatically because you are not able to know what posts you really want to expire and what should not expire.
Please, could you check the diagnostics page: Future > Diagnostics > Current Cron Schedule. The post IDS are in the Arguments / Schedule column.