Hello,
I had exactly the same issue with a Martin X-150.
After having numerous emails ignored by Martin's service staff (I would never,never,ever buy another Martin product again)
I decided to fix it myself.
Bought some pheolic from 3Rivers, rough cut it to shape, ripped the old ones off , sanded and cleaned and glued & clamped them,sanded to shape, used the nock file to make the string grooves and then sanded everything with wet and dry until smooth.
Then a coat of poly-urathane and still going strong 2 years later as my "loaner" bow for friends.
Cheers