Can't access USSD on AOSPAL

I've been using AOSPAL for a few months and I am attempting to access T-Mobile's USSD to unlock my phone . However, its just says "USSD Code Running," and it takes me back to dialer. Do I have to go back into LG Stock UI and use the USSD codes or theres a fix for it? Also Im concerned about if I flash another ROM or restore my back up, would my phone still be unlocked?