Yeah, I think that "penalized when discovered" means exactly what it says.

The FED uses other language if it wants to set some other time limits- i.e......
- R10-1-6--penalized if discovered while being violated
- R10-2-2--penalized if discovered before the ball becomes live.

They don't set any limits with the phrase "penalized when discovered" though.

Interestingly, that phrase / clause was added without comment inb the 2004-2005 book. No interps or case plays, that I can find.

I'm not aware of any either.