Do you still have 20 degree dips in night time and day temps? Did you clean everything from last grow where this was on your buds?
Definitely that same yellow mold and since its on your seed shell my guess is its in your soil.
I put my old leaves and stems in a bucket and usually put it in my lawn clippings patch in my backyard. Sometimes I forget and find that same yellow mold mixed in with all the old clippings. Looks exactly like your thread from February.
Of course this bucket is kept far from my grow room and i bring outside when I disturb to trash bag it.
This mold usually lives underground but like all mold spores is spread through the air.
You need to work on a better cannabis growing environment BEFORE you start growing and better cleaning practices. Ounce of prevention is worth a pound of cure.
20 degree dips is just asking for condensation and also mold
