if you post some head on close up pics we should be able to resolve this for you.
You may need the disc mount facing or there is something obvious that your missing in the excitment......what brake are you using ?
+1 for pics
im trying to get my head around this too
personally i cant think of what the problem is.
An IS frame.
An IS to post mount adaptor.
A post mount caliper
Fit mount to frame as close to the rotor as you can without it hitting the rotor bolts and tighten.
Place PM caliper on top and leave loose
Spin wheel then pull brake hard,hold brake and tighten up caliper bolts.
I guess you know the above
but a PM caliper has a fair bit of sideways adjustment and if the adaptor is fitted and not interfering with the rotor/rotor bolts then it should line up
Facing the mounts only removes a tiny bit of metal and is only really necessary if the brake is sitting skewed or vibrating excessively
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