Pics would help but lots of plants only have 3 blades. I have seen new growth come out twisted and then straighten out. You may need to start feeding them soon. It is hard to say without more information and pics.
sorry. the ph is at about six and ppm is at 850. I put the same strains in soil for mothers and the all have reduced bblade numbers. might it have something to do with the change in lighting. When it was cut they had 5 to seven blades. now that their out of the dome under the mh the seemed to all have reduced in blade number.