Please use commonly understood technical terms. I guess "touch probe" refers to a standard 10:1 passive oscilloscope probe?
What do you mean with "coax probe"? I guess you are splitting the signal with a simple unmatched BNC T-adapter, feeding one coax cable to your PC-Board and the other to the oscilloscope? If so, what's oscillocope input impedance setting, what's circuit input impedance? What's signal frequency?
Are you aware that T-adapter gives predictable results only a low frequencies, e.g. < 1 MHz because it involves signal reflections and standing waves?