No worries on length of time to reply, especially because now I am stumped. About the only other thing I can think of would be terrain? But even having rolling hills should not affect the sign on the building.
You could try repairing the game (in Origin, right-click and choose repair). Other than testing in a new save, I can't think of anything else atm. I'll give it some more thought and try to replicate. If I have an epiphany, I'll let you know. If you solve it, please come back and enlighten me 🙂