Update on my bug. It seems to be caused whenever the MC goes to sleep, with the only exception so far that I have found being going to sleep in the intro. All the other instances of going to sleep (like before you can go to pick up Veronica from the police station), mess up with the gauge.
Locks on stress hardly if ever reduce (simply passing time will not reduce the duration of the lock (if I choose to wait 24 hours, the lock will be in force after that 24 hours for the same amount of time as before).
And even if I edit the savegame to remove the lock, stress will not reduce by simply passing time. Basically the only way to reduce the gauge in game then is to do something stressful, like studying (even if it will not remove the lock).
It would be nice to get some sort of clarification if this is somehow an issue just on my end, or if
Faerin has made a minor error with the coding.