I have the Boot Password enabled on my Teracube 1. It’s also rooted with magicsk, although that shouldn’t be relevant. If I fluff the password on the first try, it tells me “Invalid password”, as you would expect. But after that the correct password will not work until I power-cycle or soft-cycle the phone. This really scared me the first time I observed it. I can understand it as a protection against rainbow attacks, but in that case it should probably print a warning message instructing you to reboot the device.
Thank you for pointing this out. I have marked it as a feature request that we should look at adding in future releases.