Update: I had emailed the pattern designer, Krista Moser, who promptly responded with the suggestion to pre-wash and to never dry after the pattern is complete - just dry flat and iron. She was so sweet, prompt and helpful that I had to share that with the QB folks. So nice when pattern designers are responsive and helpful.
I had already washed, ironed, cut out and begun piecing because I had figured if I wasn't happy with the linen/cotton blend that I'd just replace it but all is well. Now on to the fun part of piecing this cute project together!