It's likely that my Jericho died in the wastes between when I left my game and when I tried to log back in to it. He'd been out there quite some time, sent out with good gear and maybe he'd had some stats raised, but I'm not sure. Do you think you had any special dwellers die in the wastes? By special dwellers, I mean dwellers who show up in the dwellers section of the info section (it contains Weapons, Outfits, and Dwellers, with a description of each).
Also, is your save file 0kb or not? Mine is 450 kb. You can find your save file at /storage/sdcard/android/data/com.gamesas.falloutshelter/files/
Your save files are called Vault#.sav, where # is 1, 2, or 3.
From now on, I'm going to be backing up my vaults.
I'm also looking around online for a vault save file editor to see if I can open up my vault for editting and somehow hunt down the corruption and cap it in the noggin. Twice. With a fat man. Not the Fat Man weapon mind you, but a fat man. Gonna just pick him up and beat the corrupted part into submission!