Clumpy Throwup???

Krystan
Hey,
My LO will be 3mths Sunday. For the last 2 wks or so his Throwup has been clumpy or either very thick. At times it doesn't project out like when a baby normal throws up, it just comes up in his mouth and slowing spill out or either sit on the end between of his tongue and bottom lip. Why is this so? I make his milk as directed on cans (4oz=2scoops). Has anyone else experienced this? What did you do?