Hello Christopher!
Thanks for getting in touch and sorry for the difficulty here.
I just tried importing a CSV file and the start and end times seem to be pulling in correctly. Is it possible that you inadvertently mapped the end time column to the start time content? I’d be happy to try running your spreadsheet through my importer as well if you want to send it over in a private reply to see if I bump into the same issue.
Unfortunately, I cannot think of a way to update all those posts without re-importing them. I totally understand what a pain that is. However, I do want to give your spreadsheet a shot and rule out other conflicts before giving up.
Let’s start there and see what we find. From there, we’ll have more ideas on how to troubleshoot. 🙂
Cheers!
Geoff