Reply to Input on dealing with delay between main output and headphones?

Back after a long stint away from this great community , oh and mixing, and producing etc

Does anyone have any input on how to deal with or minimise the delay between the main output and the headphone cue on Traktor?

I've got an A10 hooked up to a DJM600 going into a Pioneer VSX-418 (No DSP - direct signal)
and the headphones' output is about 1/8 ahead of the main output making it virtually impossible to cue anything.

This isn't limited to traktor, my decks are hooked through the a10 and playing vinyl through it produces the same issue, surprisingly this doesn't happen when they go straight into the mixer, leading me to believe the A10 has something going on.

So far I've messed about with latency/buffer (192/4ms is my sweetspot), setup shorter cables for the speakers and RCA from mixer to card and tried every setting i can believe of in the amp.

A10 firmware is 48 (latest) and drivers are 3.1

I was hoping to find a DJTT video tackling this one but no luck