possibly root aphids.... take the top layer of soil off and replace it with perlite... helps with those fucks. hopefully its not them cuz they are a pain.
Yea what ever it is it's in your soil, soil looks wet was this photo take at feeding or is your soil not drying out? The curling is due to the possible start of a nute lock this also may explain the slight yellowing . Some more N should help a bit with that.
If you got bugs in your soil and you are not to far in I'd start over. Fighting those soil infections can be a bitch!! Specially if you have a garden you do NOT want to risk losing your whole garden.
Few different things to look at interested to see what you find.