Triac Z height issues

[GND]

I wondered if you're getting issues from having the boards sitting on that pink bubblewrap. It's antistatic, hence may have some level of conductivity - maybe even enhanced by humidity - so it could feasibly be affecting the connections on the underside of the PCBs. Since you seem to be getting noise related issues, I'd suggest replacing that with something a bit more inert. In an ideal world you'd screw the PCBs down with spacers off a backboard of some kind, so nothing touches the backs of the PCBs. But for starters you could always try a bit of hardboard or MDF in place of the bubblewrap? Easy to try even if it's not the cause of the problem!

[andy_con]

I wondered if you're getting issues from having the boards sitting on that pink bubblewrap. It's antistatic, hence may have some level of conductivity - maybe even enhanced by humidity - so it could feasibly be affecting the connections on the underside of the PCBs. Since you seem to be getting noise related issues, I'd suggest replacing that with something a bit more inert. In an ideal world you'd screw the PCBs down with spacers off a backboard of some kind, so nothing touches the backs of the PCBs. But for starters you could always try a bit of hardboard or MDF in place of the bubblewrap? Easy to try even if it's not the cause of the problem!

now done this and its not made any difference