"A Tremendous Service" milestone progress reset

Same here on PS4. Not sure if it helps, but it happened after playing my first match of Jetpack Cargo. As the match started the milestone for Stay True popped, which was odd considering I was nowhere near getting that one, and I was playing as a rocket trooper anyway, not Specialist. Then, at the end of the match, the Tremendous Service milestone was listed onscreen, saying I had zero progress, which I later confirmed on the main menu.