This is a misinterpretation of Rule 8 of PMC. Triple repetition is a draw,
just as in FIDE Chess--per rule Zero, all FIDE rules apply except as
contardicetd by the given rules. PMC has a differnt 50-move rule because
the essence of the 50 move rule is irretractable change--and a pawn move
in not unretractable in PMC. Triple repetition is the same as in FIDE,
therefor it isn't stated explictily in the PMC rules.
The game in question is indeed a draw if the player to move chooses to
claim it.