'burble' and 'starving 4 fuel'?
Those are opposites (rich/lean), so I'm not sure what the situation was.
Still, some 'common' stuff:
First...what you're dealing with is a 'hot soak' situation. In as short a time period as your 'break', the engine temp probably rose a good bit from operating temperature. That's enough in itself to maybe give you a starting problem.
If the vent hose was 'lightly sucking air'..that sounds like a dynamic situation? Something that was ongoing? Shouldn't be. Pressure in the gas tank should be ambient atmospheric. Shouldn't be UNDER pressure or vacuum, either one. Not for any extended period (minutes) of time anyway.
Was your gas turned off?
On the sidestand? Know if it peed or not while sitting?
Did you turn the gas ON before you tried to start it....or as is the habit of some..did you try to start it FIRST, then turn on the gas? (No, I don't know why they do that).
Next time it happens, turn off the petcock, lean the back full-over on its side for 10-15 seconds. See if that makes a difference.
No...it's not 'normal'. There is something going on either with method or manner or the bike.