Reasons for glitches observed on PCB from physical touch of floating enclosure
So for those that may be interested, I looked closer at this issue with a PCB we received. It appears the glitch induced was working its way to the input of a Schmitt trigger gate with a too high a pull-up for its input impedance, giving it quite a high sensitivity to perturbations, and propagating the glitch to the D-f/f clock ... in brief, having turned the weak pull-up into a strong pull-up and including a simple RC filer on the input pin as an added precaution it looks all good and dandy, no false triggering regardless of how much I try ... nevertheless, thanks to all those with the added comments....