That's because there's a newer build after MMB28V the 6.0.1 (MHC19I) build.
you should do the following
apply update via adb
make changes again
or if you want to do it without flashing factory images
I'm planning to downgrade to MM due to the hideous Android OS and Android System battery draining. Getting hardly 2 hours of SOT with very light use. Anyway I know that I'll have to flash the factory image but there are a lot of model types and I ...
What version of TWRP are you using ?
Look into cerberus, it allows wiping of both internal and sd card.
Plus its dirt cheap and a good app.