I'm not sure if you can do much about this one, but as I'd rebooted my phone I was back at the 'master password required' phase rather than being able to unlock with touch id.
Having used the extension (to log in to this forum!) and having had to enter my master password to use it rather than touch id, when I went into the app I needed to enter it again rather than being able to unlock with touch id. Since I had already 'unlocked' the vault when using the extension I was expecting to be able to launch the main app with only a thumb print. Hopefully this is within your control but I am wondering if this may be an apple restriction.