User error? LV long shutterspeeds get reset to 1/30th

[AtomicTurnip]

Help please! I'm shooting a dark scene (in M) and have set a slow shutterspeed (2s for example).

When I go into live view (to use 10x focus) the shutter speed suddenly changes to 1/30 regardless of what I had set before; when I quit back out of live view it remains at 1/30 unless I change it back.

What do I need to set so that I can keep my shutter speed at 2" when in live view; please?

5D2 v2.1.2. Nightly build 2015Sep29 and 2015Mar03. It didn't used to happen in older builds, but unfortunately I haven't kept those...

[AtomicTurnip]

Case solved: Expo menu, select LV Display, select Photo, ExpSim.