Hi! I have a tech problem that Amazon’s customer service can’t seem to handle and I was wondering if you all might have some ideas.

I use Kindle on several devices — an iPhone, a Paperwhite, a Boox Nova Air, and a Supernote. Until recently it was fine, but now the devices don’t sync their activity. One will show Book A in top position, another will show Book B in top position, and so on. Hitting the manual sync buttons doesn’t help, and neither did resetting devices, de registering and reregistering all of them (ok it worked for a second, but quit working the first time I opened a book), or fiddling with the whispersync setting.

The problem started shortly after I started heavily using the “send to Kindle” function, but that might just be a coincidence.

Have any of you seen this before? Do you have any ideas of things I could try to get my devices aligned again?
If you expect to see the same order of the book thumbnails in your "Library" all across devices, then sorry, no.

Each device can have its own "Filter" and "Sort" settings, which Amazon never syncs that settings across devices.

But, with the same account, all devices will see the same number of books/documents.

Make sure you turn on WiFi/4G, have the same "Filter"/"Sort" options, and sync all devices.
I think they meant the order in your home screen? Probably.

I also use send to kindle, and I did notice the books on the home screen aren't syncing properly.

I remember before that if I opened a book on my kindle, the first book in the app's home screen would also change to that book, and vice versa. Now, though, the books on the app's home screen doesn't update anymore, unless I open a book using the app. Weirdly enough, syncing from the app to the kindle seems to just work fine. My Kindle's home screen would update whenever I open a book on the app.

I haven't used the app in a while so I'm not sure when this started, but I noticed it happening a week or two ago.
Yeah! That’s what I’m experiencing. Even if I have the same view set up in all my devices and they’ve all been manually synced, they all show different orders of the books. And it’s also been going on for me for a few weeks. And a few other things too, like when I hit “return to public library” on my library books it says OK but then the book cover is still there the next day.

If it’s happening to you too then maybe it’s a larger glitch and I should stop deleting and reinstalling everything trying to fix it, haha. Thanks for your response
It's most probably a glitch. I don't have a public library system from where I'm from so I can't say I also experience that. But I did discover there are some titles on my Kindle that I've already deleted, and their covers are still there. Nothing happens when I delete them or remove them from their collections. It only went away when I opened the Kindle on my computer and deleted the files related to that title (the book file is missing, but the other files are still there). The kindle probably glitched out when I originally deleted those books on the device.

If it doesn't bother you that much, I suggest to just let it be. Not worth resetting the kindle every time it happens.

As for the original issue. we just have to wait until Amazon fixes it. They just probably turned off a switch somewhere because app to Kindle sync is still working somehow.