All-Day calendar event spans over two days on iPhone

I have this problem as well but could not reply to the original question. Just got off the phone with Apple Support. I have multiple devices and I keep my calendar on icloud to sync on all devices. She had me go to my iCloud and uncheck it. This brought up a box that Gave 2 choices, ‘Keep on iPad’ or ‘Delete from iPad’ because I keep my information on icloud we deleted it from my iPad. Waited one minute, then rechecked it in iCloud. when I reopened my calendar that solve this problem for me.