iPhone 16 Calendar data disappeared then reappeared

This is a question with a quasi-solution. After I updated my iphone 16 to iOS 26.1, I was adding an event to the calendar when for no apparent reason, all the calendar data disappeared. I couldn't see anything in particular that I had touched. I went sequentially through each display preference on the calendar screen. No luck. I power-cycled the phone. No luck. I tried again the next day. No luck. I finally called Verizon. As the tech began to troubleshoot, I looked down, and everything was magically back, though in a format I did not want. I tried to change it and all the data disappeared again and none of the troubleshooting he helped me do worked. He went off to check for more solutions. Meanwhile I clicked the calendar icon at the bottom right of the screen and went through each calendar option and clicked on the information button, then closed it without changing anything and then went back to the calendar. At the end all my calendar data came back in my original preferred format. I'm relieved but wary since I don't know why the problem happened in the first place, which means it could happen again. Posting in case you have ideas about what happened and in case this solution helps anyone with a similar issue.