An non-conspiracy would be that iOS confused deleted data as corrupted data and recovered it, although that's quite a bad bug, although maybe it just happened during a deployment script I guess?

Remember: deleting data only removed inodes, not raw data: the raw data get overwritten with time. The more full you storage is, the faster that data gets overwritten.

iPhone have a lot of storage, so yeah, most likely a bad deployment script. Still not good for such a company.

A conspiracy would be a worker tasked by NSA to introduce such a bug to keep deleted files as long as possible, "just in case", for spying matters.