In my experience, the double login issue seems to happen when restoring after having run out of battery. It happens on my ~2013 macbook as well.
A completely unscientific assessment is that the first login is to authorise restoration of the session. Unfortunately it seems like that authorisation can't be passed onto the session itself, so that also needs unlocking.
A completely unscientific assessment is that the first login is to authorise restoration of the session. Unfortunately it seems like that authorisation can't be passed onto the session itself, so that also needs unlocking.