What kind of fabrics was it? I've had that happen with solid cottons -- I think they were quilter's candy-- from Connecting Threads. It's ok fabric for the price, but you really don't want to go pressing with steam until it's been quilted, or significant shrinkage occurs. I was lucky that I had my shrinking moments before I cut, but it was still alarming to actually see the fabric drawing up smaller.
Cutting that many pieces makes me wonder (just a wonder, not a criticism) why the class is not making this an opportunity to learn about strip piecing as a means of avoiding having to cut so many small individual pieces?
RST
RST