I have a site that I built for a client that has been working fine for the last 1-2 years, but now the Date Time picker is no longer showing the calendar when editing custom posts in wp-admin, if I add the date as a correctly formatted string then it saves correctly.
I have tried disabling plugins but the issue persists, it seems to be from updating to WordPress 5.0.3 but not sure exactly, the site is running ACF Pro 5.6.7.
What would be the best way to debug this in order to fix?
We had the same problem and have a solution for the date time picker to work well.
You just have to update your version of ACF, I think they made a correction for that.