It might be a plane selection issue?
G19 selects the Y-Z plane. R word is generally difficult for more than 180 degree arc. might want to break down command in to 90 degree quadrants if using R word.
what you're doing can only be done in a mazatrol manual milling unit. I forget if you can even input G19 on T+ control?
chamfering a cross hole works beautifully in mazatrol though. whats your objection to doing this"mazatrol way"?