What's up with these new sprouts?

I have a simple DWC setup with lots of bubbles wetting the underside of netpots. Germed seeds were set in the pots with rapid rooters and hydroton 36 hrs ago. This am all but one has formed a small sprout with the seed case still on. All good so far. But 2 of them have a white fuzz on part of the stem. Is that mold? The rapid rooters aren't getting any wetter than when I used this method in the past, and I had no problem then. I took the humidity dome off. Is this a problem and what can I do?

Pictures speak 1000 words.

Here's a pic. There is another like this that looks the same. I'm thinking of lowering the water level but it is at the same level as the last grow and no probs then. However, I have new boss hog airstones so maybe more bubble action. I'm stumped - never seen this.

What are your stats? pH? Ferts? Temps? How far ar the lights? Type of lights?

It's hard to tell, but the white fuzz just looks like what you see on the major tap root naturally, it's not mold and I'm pretty sure it's not a fungus as I just re-checked the roots on my babies and they have this going on on all their major roots.

I wasn't sure that it was mold, just worried because it is only on 2 of 6. These are only 36 hrs old so no nutrients yet, water is ro with pH6. No green yet so light isn't really needed but I do have a single 90w led/ufo about 20 inches over them. Temps are mid 70s. Humidity was up to 55 but I let it fall to 40.

I wouldn't worry about it. Maybe push the seedling down a little so it's deeper in the substrate. If you do, be VERY careful of the root.