Disease in seedlings?

[Utes1972]

Hi All,

This is my 4th spring starting my plants from seed and I've never ran into issues up until this year. My plants are about 4 weeks old at this stage, being grown in my basement at a temp of around 60 F, had heat mats only during germination. Fan on intermittently throughout the day. Under high-intensity LED grow lights for about 14 hours daily. Everyone was looking good until literally the last 48 hours when 5 of my 20 starts rapidly developed twisted/contorted new growth and odd thickened/fleshy- almost gall-like lesions on the leaves. One of the plants had yellowing of its lower leaves but that alone wouldn't have really caught my eye. I immediately removed these plants from cells and disposed of them after taking pictures but I'm hoping to get some idea of what happened. All the seed is fresh and from reputable sellers who I have bought from previously. The seeds were planted into sterile media.

Any ideas? Thank you for your time