de facto,
There is no extra protection with the bleed switches on. The protection circuit is powered directly through the dc bat. bus. Additionally the overheat/overpressure switches command the PRSOV closed, which is already closed during starting, hence no start protection.
I am curious about where in the AMM it says differently, I don't mind being proved wrong.
Edit: I see where you read it, AMM Chapter 1 36-11-00 pg.27. Its referring to the ACAU closing the PRSOV through the start relay, that's the start protection. But, with the bleed switch off, the PRSOV is already closed.