I suspect that it was just unlocked when you had disconnected the cable.
There is not reflection now. It seems that it is now misaligned after the alignment work.
So what you need is "align while scanning PZT -> lock -> align".
Unfortunately, after the measurement when I unplugged BNS connector from the laser, I misaligned PMC. For several hours I adjusted the mirrors but could not significantly improve transmitted signal. I'll return to this issue tomorrow.