Paste Tomato issue

Hello everyone. I am having some kind of issue with my Paste tomatoes. The look like they have some kind of edema and I don't know why this is happening. It doesn't happen to my other tomatoes. It also happened last year with different seeds from a different seed company. This year we also started soil blocking and all our plants are doing much much better. Please see pictures for reference.

Thank you everyone!

Looks to be damping off, fungal/pathogen borne, get rid of ALL suspect seedlings.  Don't touch anything plants/planting, gardening related without 1st disinfecting your hands/clothing, tools, etc .  I use a soilless mix to avoid the possibility of damping/fungal/pathogen problems. Cool, damp(poor drainage) mediums encourage the problem, tomatoes in particular are originally tropical plants, warm feet and well ventilated heads and they grow

We also have a fan circulating and were previously on heat mats to germinate. Would you recommend keeping the heat mats on after they have already germinated?

How do you provide for their light requirements? I wonder if they might be a touch leggy (over-extended)?

Heat mats are my new trick if I have a houseplant suffering from overwatering. Anything to help evaporate off some water helps in my mind.

Keep them on the mats, the warmer the better. The mat thermostat is set at 85 for ours and the probe is set under the tray out of contact with the mat.  I transplant, in our case into 6 packs for the stand, as soon as the cotyledon's flatten out, then onto the greenhouse benches, day time temps in the 75- 80 range and night 10 cooler, surface soil ever so slightly dry between watering's w warm water. As they get bigger 1-3 leaf stage I move them to cooler, like 5 drop, parts of the grnhse which acts as a slight hardening, then when they're at 65-70 rang out onto the stand. For the field it's transplant again into 3x3 pots wait for the 3rd week of may and into the ground. It's a lot of fussing , makes my wife nuts at me, but we sell out year after year and pick pails and pails full

What I can tell you is that some adult tomato plants developed edema in my greenhouse last year when the temperatures went excessively high and I didn’t have the ventilation figured out yet.

It does look like the first stages of damping off. In my experience, this comes to them staying too wet. I had this happen once or twice when I was starting tomatoes in soil blocks. Make sure the blocks can dry out enough, but not so much they the blocks form a crust. Always water from the bottom with soil blocks.

They also do look a bit tall compared to the leaves coming on, so they could be a bit leggy.  A brighter light can help them be more stocky, which is what you want in the beginning. The fan too, but you already said you have a fan blowing on them.

Lastly, don't be too worried. One year, 90% of my tomatoes were damping off. And I transplanted them higher than the damping off point on the stem... and they all survived and did fine.

In my nursery, we water from the bottom and sprinkle ground cinnamon around the seedlings as they appear.

Cinnamon is a natural antifungal and helps in cases of damping off. Hope this helps.

Make sure any cinnamon you buy doesn't have fillers or bulking agents like flour added, check the jar before buying. It lasts a long time as it should be scattered sparingly, not thickly.

I was just listening to a no till market gardener podcast where a sugar water spritz was suggested as a remedy for damping off.
Apparently it works by feeding benign microorganisms and they overwhelm the fungus that causes damping off.