I've had somthing similar:
Sometimes when I try to warp out (retail and MOD) I get that twittering noise and "Subspace drive engaged" up.
Then the warpout sequence stops with the 'warpout aborted' message.
Sometimes it doesn't even get so far as making the key press noise.
I'm not under fire, not about to crash into something - sometimes it even goes when I'm on my own; not another object in the mission.
So not the same, but related, perhaps?