Sounds like she's trying to adust the front d on the limit screw alone.

She tightened it so the chain wouldn't drop but allowed the chain to drag on the cage. On your return, I'd bet she loosened the limit screw allowing the cage to move to void chain drag. This put you back to point A.

First time she should have adjusted the limit screw, then adjusted the tension to keep the chain off the cage. Sounds like she just bounced the screw back and forth....find a better mechanic.

Proper front der adjustment is finding the right combo of tension and limit screw position.