LOL exactly on the same pagesome strains root fast, some slow, some not at all. if the temp of the cubes is too high, the plant stems will soften and won't make roots. I'm not a fan of those mat's for rockwool cubes at all. I've lost many seedlings to just a couple of degrees to high with that crap.
all you can do is wait............if it makes you feel better I've had strains take 20 days in an aeroponic cloner.
lol curious.....we're on the same page tonight. just saw your post hit the same time as mine.