iPhone contact phone numbers changed format, displays "Maybe:"

My iPhone contacts all changed format for some reason and now known, already existing contacts in my phone appear as "Maybe: (contact's name)". The phone numbers no longer appear as +1 (123) 456-7890, but as 4567890. If I manually edit the contact number back to the correct U.S. format it works fine. But is there a solution to fix all contacts at once instead of going one by one? My region is already set to U.S. I tried changing to another country and then back to U.S. as some others have recommended but that didn't work. Neither has multiple phone reboots. My iPhone 8 is on the latest iOS 12.4.1.