Hey buddy, thanks for reporting. Is this in the Ogre/Grendel operation? I think I'm beginning to see a pattern which I can use to debug what causes the problem.
I also encountered the same bug in the Dust Lance operation. On the final airfield assault, all targets are destroyed, but then no further voice lines are given and the airfield is not marked as "friendly" like it should when that operation completes. I have completed that operation before, and didn't see any of the usual indications that it "completed" this time.
One thing I did notice is that the last red marked enemy tank was destroyed by an ally. I do not know if that was the cause - I will need to try the mission out a few more times to see if I can replicate this.