For some reason I don't like having the Reg in on the surface.
I test breathe it before I drop in, but if I leave it in place for longer than is necessary to do so then I get the urge to spit it out. In the water I don't have a problem. All is good. Must be a mental thing.
The last couple of sea dives I have had a similar problem when I surfaced. I didn't think too much of it. On the surface, bouncy bouncy, swallowed a mouthful of seawater that got passed the big toothy smile, back on the boat and bleurgh .. feed the fish.
It was only when I was using the same (light cylinders) to perform a buoyancy check that i noticed a vague sense of an unsettled stomach. It occurred to me that the gas I was breathing might have something to do with it. I was using Nitrox32.
I don't keep the Reg in on the surface as a rule.
I'm curious to know if this is just me making something out of nothing or whether others have experienced the same thing.