Oakley's seedling death 2019

[oakley]

April first I noticed a bit of funk in one tray. I was starting to pot up what I had time for...
Not seed quality or soil having tested previously. Good seed, same soil.
Gardener error but can't figure out what I did.
I sow 3-6 seeds per cell, pot up 2, put one back in the same cell for back-up.
One tray went south fast.
Lower left in pic.
Three varieties did great without incident.
Curious what the dead and suffering have in common...carrot/frilly leaf?
KARMApink is tissue paper potato leaf at that age and it thrived.
....more pics to follow as I figure this out...