I can confirm this, as well. Since I am the one who placed the demo charge, I am fairly certain that what happened was that Objective D was blown up while controlled by the Japanese. I recall that we had captured it, and as I was moving up to blow it, the Japanese captured it back. There was also a problem where I placed a demo charge on Objective E twice, and it never registered as having been blown up. Here's a screenshot in of the map, in case that helps.