I have it happen on my DB once and a while. Chop an un activated head down so that the pressure is off of that set of floods, then turn the knob see which one is loose, tighten the two allen screws a little. Probably should go around the machine one at a time and check them all, you are fortunate that they are going up on you. I've had it where the flood was going deeper and cut into a screen on a double stroke in the middle of a job and wreck half a day. I now check them all monthly just to be preventative of another episode like that.