When iPhone 6Plus, with current iOS, syncs with iTunes, I'm told the updated apps aren't compatible
Since iTunes says this is a problem with my iPhone, I'm asking here instead of the iTunes board but I admit it may be iTunes.
My iPhone 6+ has 8.3 which is current.
Recently, if I update the apps via iTunes and attempt to sync, some of the apps are not updated and I get a message saying that the apps weren't installed because they are not compatible with the iOS version on my phone. It recommends updating the iOS on my phone.
If I then go and update them directly on the phone, the very same apps that iTunes said weren't compatible, update perfectly on the iPhone. Furthermore, if I now sync a second time, there are never any error messages. It syncs perfectly.
This doesn't happen with same apps each time since none have had two updates since this began but this has happened with at least one, sometimes more, each time I sync if there are apps in iTunes that are more up to date than those on the phone.
...and it doesn't happen with every app being updated. In other words, iTunes may gag on one or two but update the others happily.
Newest iPhone software and newest apps. Any thoughts? What am I doing wrong and why is this happening? (Yes, I know I could just continue to update via the phone itself.)
Thank you for your kind support.