Deep search analysis JA's signals on ZL4OL's capture

The original argocap from ZL4OL (10:21 - 11:50 UTC):

JA1CGM is on about 137778,2 in QRSS120
Who is it on about 137776,2?

The original file from 7L1RLL's grabber (11:33 - 12:20 UTC, Date 2019-04-03 !):

JA1CGM is on about 137778,6 in QRSS120
JH1OFX is on about 137776,6 (dot) in DFCW60

This is a merged file (ZL4OL's original + 7L1RLL's part)

I believe that at 137,776.2 seen JH1OFX's callsign part "H"