On another forum, there is a member whose natal 1st house Saturn is conjunct my natal 3rd house Mercury, in Scorpio.Over time, our interaction on that forum became one in which I felt like a child being constantly criticised by him for grammatical errors ... which is a classic negative manifestation of Saturn-Mercury synastry aspects.
However ... our natal, synastry, composite and davison charts did not reveal/explain why he seemed (to me) to be "channelling" his mother's values rather than his own.
But ... when I compare each of our two natal charts to our composite chart ... the latter's Chiron (in Capricorn/3rd) is conjunct my natal 4th house Jupiter and trine his natal Moon in Taurus/7th (and my 8th house, of other people's values).
And ... the relationship eventually broke down completely because of my frustration with his 'inability" to see that he was channelling his mother, rather than because of the Saturn-Mercury criticism itself.