[Sailor Steve]

I know this will sound weird, but how are you trying to raise the periscope? Are you using the on-screen switch, or the keyboard buttons? The reason I ask is that the two scopes are raised by two different sets of keys; one is page-up and page-down, the other is insert and delete. There have been problems in the past with players looking through one periscope and hitting the keys for the other one.