Also - this can't possibly be related, because the cassette I took off had only been installed once, with the new crush washer - but it was loose when I went to remove it. Not loose enough to rattle, but loose enough that it took very little effort to remove. I'd used my good Snap-On torque wrench to install it, as always, so it wasn't undertorqued. Why would it be loose? [/QUOTE]

is it the deformed one you're re-using? did you try hammering it flat? If it's loose then I'd be worried... sometimes people don't put things together properly the first time either, maybe the shop just grabbed the wrong washer in the first place when they built it? or maybe you put it on backwards? I always accidently put things on backwards, lol!