Why does my iPhone calendar want to default to putting new events to the following day?

Since updating, it seems that my iPhone 11 on iOS 17.4.1 wants to create new events on the day after the current day. I need to change many events from the next day to the current day. I am not sure what the glitch is.

I do understand that that prior to updating, I was troubleshooting with an agent, who had me switch from a calendar that was synchronized with an e-mail server, and match it with the iCloud server. I noticed today that at least some of the events that are automatically created on the following day appear to be stored on the iCloud server. If somebody may have seen this issue, and knows how to resolve it, please advise. Much appreciated.