Did it look like little grapes? That kind of formation? A bit more squishy and shiny? IF so, then most likely what you were seeing is cecal pellets. IF that is the case, most of the time we don’t see this stuff because bunnies actually eat it. I know that is gross, but that’s how their wild cousins have survived with little nourishment. To explain it as simply as possible – basically their digestive system has a certain type of bacteria that breaks the food down and stores an extra nutrients in the cecum – like a little pocket, then from the cecum comes this highly nutritious icky stuff, and they redigest it. This usually happens only once day.
If you start to see this happening more often where your bunny is not consuming it or it’s getting worse then either it’s that Pumpkin’s diet is too rich or there is another reason for this and pumpkin should be treated by a vet.
If it ends up looking like one messy glob, not little clumps, then that is also a problem.