I would suggest that it's time for either a mast head amplifier or an amplified signal splitter to replace the current passive one. There may be other factors which can only be identified with the benefit of local knowledge.
I'm a bit puzzled by the possible suggestion that installing the new set has suddenly produced problems in the previous set(s) which were not apparent up to that point, but I may have mistaken your description (still morning here and the coffee has yet to kick in).
Getting a specialist in might be the best option, but watch out for over-servicing ie a complete new system which may or may not be warranted.
FOR