My mentor told me to stop quenching in water and I ignored him for 3 weeks

Old Dale at the forge in Abilene told me back in March that water quenching my 1084 blades would crack them, and I nodded along but kept doing it because it was faster. Three weeks later I pulled a hunter out of the bucket and heard that little tink before I even got it to the bench. Sure enough, a hairline crack ran right up from the edge. I switched to warm canola oil like he said, and I have not lost a single blade since, which stings a bit because I wasted about 6 blanks learning it the hard way. Now I preheat the oil to around 130 degrees with a scrap piece of steel and it is way more forgiving on thin edges. Anyone else had a mentor call something that you swore was fine right up until it wasn't?