Data Loss(?) with Nitrokey Storage

I’ve been using the Nitrokey Storage for a year or so with Windows now, and recently after inserting and mounting the encrypted volume, it displays in Windows Disk Management as a RAW volume. To attempt to see what was going on, I attached the device to a Linux VM with nitrokey-app installed. After using ddrescue to dump the block device to a file (no read errors), I ran testdisk on the image - it said that the primary and backup FAT tables were correct but not identical, and the dirty bit was set. Attempting to browse the filesystem with testdisk showed the general folder structure, but the majority of files were missing. Allowing testdisk to fix the FAT headers and mount it with a loop device showed many garbled filenames, and input output errors.

Is my device hosed, and is the data recoverable?