I wonder if Vinnie has a problem with pumpkin? Have you ever given him other versions of pumpkin before? There really isn't much in there, but maybe it's enough to cause the soft poopage. That's the one I give my guys most often and have never had a poop issue afterwards. I'd hate to suggest trying one of the plain chicken flavours and have Vinnie go through the same thing again. How much did he eat? Maybe it was a volume thing more than the contents. I usually split one of the small cans between 4 cats.
"To close your eyes will not ease another's pain." ~ Chinese Proverb
“We must not refuse to see with our eyes what they must endure with their bodies.” ~ Gretchen Wyler