We can read in 802.3, =A7188.8.131.52: "The normal use of the /H/ indicator is for repeaters to propagate received errors".
This operating was needed when the hub linked interfaces with different signalling codes.
But I don't see the using of the /H/ code-group in a FD 100Base-X switch. The switch discards the frame in error at the level-2.
So, it seems that the /H/ code-group is never used with the FD 100Base- X switch (perhaps just in the jam signal in half duplex).
Is it your advice? Michelot