Photos app on Catalina not showing preview of photos to import from iPhone.

After updating macOS to Catalina and iPhone 11 to latest iOS when I try to import photos from iPhone to Photos.app on Mac image previews are not loading. Occasionally first 30 or so will show up, bot nothing else is showing. Photos are importing fine when selected, but it's annoying as I don't want to download all of them, and I'm unable to select which one I want to import without a preview.