The potential for an altitude bust was clear with this clearance so I asked a plain English question. “Confirm you want us to stop the climb at 15,000’ “ She said “negative ,climb via the SID means you climb to the cleared altitude of the SID which is FL230}.whilst all four of us believed “climb via the SID except maintain 15,000’ “ ACTUALLY meant we were to stop at 15,000’ her last statement cancelled her previous “maintain 15,000’” so our reply (to be clear to her) was “roger climbing to FL230”
yeah she screwed up. Maintain 15,000’ means stop the climb at 15,000. She probably didn’t realize what she said in the first place.