Ploppytheslopper in the land of Oz.
I have had a pro qdi3 for nearly 3 years. A great BCD (The only one I have ever owned, started diving late in life)
I did have a problem a couple months after buying it, The lower rear dump valve stuck on open, which rendered the inflate/deflate function useless.
On inspection I determined that the nylon push rod that operates the valve had slipped from it's seating. the seating is a hole about 1mm deep in a nylon spring loaded block in the valve housing. Not only had it slipped from the seating it had jammed under the block, holding it open. I feel that had it not jammed under the nylon block that the spring loading would have closed the valve allowing oral inflation and manual deflation via the oral inflator.
A failure of this kind could lead to major problems at deeper depths particularly if you are negatively bouyant. (In oz we pronounce it boy-ant)
To this end I always, ALWAYS.....carry an oceanic zippered PSD, It can be used as a safety and bouyancy aid at the surface as well as in a rescue situations. It is inflated and deflated via a mouthpiece similar to the oral inflator on the Pro qdi3. and in a critical situation could be used in a freewater ascent to control bouyancy.
I had the BCD looked at by the supplier, who deemed it to be okay, no probs.
But it's my life not theirs.
Live long and dive well
ploppytheslopper