Hmmm. Battlefield lasers?
ZZZZAAAAAP!!
That was the first thing that popped into my head. We've been shooting down missiles with lasers for twenty years in our R&D programs, and it wouldn't surprise me at all if we had deployable assets of that type. And "inflight motor failure" is THE failure mode for a laser intercept. I've seen footage of anti-missile laser tests and it is a very discrete way of knocking out a missile; you don't see anything, but the missile motor suddenly eats itself in the same way it would if there was an engineering failure.