This has been reported before btw. i just saw one that had this same issue.
Have you thought to check to see if your connected to Xbox Live Services? The last time I ran into this issue was when I could not connect to Xbox Live Services in December. One way you can check is using a windows 10 computer if you have one.
I have also ran into this issue, however it eventually stopped. I don't know what all causes it though. i know mine started after they got Xbox Live service back up, but that was the only time.
no. nothing is a .zip, .mcworld, or .mcpack, even though if you put a .mcpack in minecraft loads it.