That’s an excellent question.
It seems there is a problem with how dates and timezones were saved for your posts, I’m not sure why.
What I would suggest, if you don’t have too many posts, is to go through each and save them again. Without any modification, just a save. Then try to regenerate the boards without the fixes we implemented and see if it works.
There’s also a chance the issue is with some of the posts and not all.
If that doesn’t solve the problem then you can either hire someone to try and fix it permanently or keep that fix somewhere and put it back in place after each update if the problem persists.