center lock disc issue

I cannot get these rotors to line up, or shall I say I cannot get the caliper/pistons to operate centrally on the disc.
One of the pistons always touches the disc first and pushes it slightly.
Disc is RT 81 Ice tech and is brand new.
I have tried multiple brakes with different calipers but get the same results.
The disc is true.
Pistons on the calipers move equally off of the disc.
Currently using a m785 brake, tried with old style m395 which have br 477 calipers and tried with m615 calipers, all end up touching the disc slighty on one side before the other, any one ever had an issue with center locks?
One of the pistons always touches the disc first and pushes it slightly.
Disc is RT 81 Ice tech and is brand new.
I have tried multiple brakes with different calipers but get the same results.
The disc is true.
Pistons on the calipers move equally off of the disc.
Currently using a m785 brake, tried with old style m395 which have br 477 calipers and tried with m615 calipers, all end up touching the disc slighty on one side before the other, any one ever had an issue with center locks?
0
Posts
Loosen caliper bolts
Apply brake
Tighten bolts
Release brake
NukeProof Mega FR 2012
Cube NuRoad 2018
Previous:
2015 Genesis CdF 10, 2014 Cube Hyde Race, 2012 NS Traffic, 2007 Specialized SX Trail, 2005 Specialized Demo 8
I found a m506 that lined up nicely but feels a bit spongy so might need a bleed, never had issues before, tempted to try my other wheelset which uses 6 bolt disc to see if it chances anything, the ice tech discs look a tad thicker.
The m506 came off my 26" xc which had 6 bolt disc and it felt really solid, put on the center locks and it's not so great, seems a bit strange.
I seem to remember that it is the case and need matching shimano callipers.
Having said that, I have a pair of them, these are the earlier model without the fancy alloy cooling fins, and haven't noticed them being thicker. They are running with matching xt calliper.
....but it as long as the pistons move apart to let the disc in, it shouldn't matter as the hydraulic pistons are self adjusting.
Weird isn't it, how we are all different?
I don't mind a bit of lever travel, as long as the lever goes hard at the end. I prefer to feel the brake start to engage almost as soon as I move the lever and then progressively get firmer and firmer. I haven't measured the travel, but just visualising it now, maybe an inch of travel (25mm) from fully off to fully on?
My 11-year old grandson is the same (of course he is, I trained him and set up his bike!) But his mates nearly always go OTB when they test ride his bike. They complain "why are your brakes so fierce?"
@thecycleclinic
It is difficult to move the caliper left and right on the I.S to Post adapter so could be an issue there, I think I have some new adapters somewhere but the fork was brand new, only done maybe 100 miles, Salsa Firestarter.
Is there any known issues with air in the lever of the m506 levers?
They are just not as solid as I would like, fully bled, burped with the funnel, does anyone ever do a bleed from top to bottom rather than shimanos bottom to top method?