I planted sugar snap peas and about half the plants grow pods that look like they are shrink wrapped over the peas. They taste fine but texturally are different than the normal pods. They are in a double row growing up wire strung between two six foot posts. They are six foot tall and very healthy vines. The vines are producing very well. The pods are thinner than they should be but the peas are proper size. They remind you of a rib cage on a too skinny dog. I have gardened for years but my first run at sugar snap peas. I don't believe it could be a water problem as the plants that do this are interspersed with the plants producing normal pods. Any ideas?