Kindle app on iPhone always sets the furthest page, ignores iPad kindle

I use Kindle on my iPhone and my iPad. If I open the same book (Amazon unlimited book) on both devices, later when I read several chapters on my iPad, close the app, and reopen it, it says the furthest page is on your iPhone.

for example, I’m open the book on the iPhone and then tell it to sync. Close phone app. I open the same book on the iPad and read to chapter 8. When I reopen iPad, and click sync it says the furthest is my iPhone on page 1. Screen print attached below.

same version 6.83 on both, same Apple ID, whisper net active on both, etc.