Please help needed

hello guys, i cut clones from my mother plant every 2-3 weeks.
i use SERADIX B cloning powder and normally hava a success of about 80% in total clones which get roots.

but this week, i cut the clones and do same steps as before. but after four days the clones started to crack at 90degress. see the picture below. today all my clones died.







all of my 40 clones are showing the same characteristics = bending at 90degress.

could anyone help me with this issue. your advices are really appreciated.

more information =
mother plant is under a 400w hps.
cut the clones every 2-3 weeks, dip them in the seradix powder, place them in the jiffy pellets, finally put them under a dome exposing them to a 400w hps about 2-3 metres away for 18hours everyday.

troubles =
small clones starting to tilt down, but after 1 week now, all are broken at 90degrees.

could anyone tell me when am i doing it wrong,
i don't want to loose more clones.

Either someone snuck in and pinched all your babies, lol!
Or you've got an embolism problem.

Thats a tuff one, there's a lot of variable in there, especially when you say you've been successfully doing it the same way with the same plant. Are you maybe using too much hormone on too small of cuttings?

Try not using the dome, instead just do a daily mist. That's the only thing I can think of.