Stump lab won't open (Xbox one)

My save is over 120 days in. I have defeated the assistant manager a while ago and already have the keycard for the koi pond door. When I entered the small lab room for the first time, the button to the stump lab was already pressed, despite me never entering that room before then. Even the door accessed by the assistant manager keycard was still locked. I figured if the button was already pressed, that meant the stump lab was open. I went up to the stump lab and the door is red with the message that it's still locked. I tried looking on Google but all it says is to make sure you have the assistant keycard, not what happens if the button is already pressed before you even reach it. And yes, I unlocked the door with the keycard leading to the chest with the right side charm in it, so that room is fully explored now.