Ugh, my friend Jake at an auto supplier had this happen... Their CAD model for a bracket was perfect, but the prototype came back wrong. He spent hours trying to 'fix' the digital file instead of just redlining the print. Missed a whole batch because he couldn't visualize the manual change... Said his training was all about perfect 3D models, never how to correct a flawed one. Now he's begging the old timers for sketching tips.