I usually use the Hole "Wizard" (silly name) to create tapped holes. I use the display option of pilot holes with cosmetic threads. It all works fine, but later on when editing other features, the cosmetic threads sometimes increase in diameter, to double or triple their correct size. They appear this way in both parts and drawings.

It looks ridiculous, and it's misleading to the shop to give them a drawing looking this way.

It appears (from limited experimentation) that I can fix the error by going back into the "Hole Wizard" (sheesh) and clicking the green check without changing any settings. But why should I have to do this?

This is with SW2011 SP5.0, but it happened with previous versions also.