Also a Lumia 640 LTE but in my case the phone became so unstable (locking, apps crashing, Outlook mail & Calendar refusing to open) that I finally reset my phone. I now have apps which I own and are available, but will not install. I have others that are giving me an error attempting to update. Of course, there are those that just disappear from the store without any logic at all. Just now, my phone froze for the first time since I reset it 3 days ago.
I'm also a Microsoft Band owner, and it still looses connectivity with my band and typically requires a reboot to restore the connection.
I'm hopeful that another update is coming soon and hopefully corrects the glitches I have. I was thrilled with my 640 on the build prior, but this is becoming frustrating.