I use morale mostly as vigilence to reduce damage for my front liners. Now the vigilance is randomly, without any discernable warning, just dropping. There are no standard number of rounds, the mechs are not being punched, and they are not unsteady. Is this a bug? It's rendered the game so frustrating it's unplayable (Currently a 1 star game). Anyone know a fix?

What do you mean with a standard number of rounds?
Viligance only last until the Mech is activated again or until you skipped his turn.