Fourth Star in Mopping up Blitz France

[michaelguth]

this may seem silly, but it bugs me that I can't get the 4th star in Blitzkrieg France, for 'Complete the Mission in 15 turns'.

A. I capture both Bridge objectives in 15 turns, or 13 or 12 in easy mode.
B. I destroy not only 30 units but 50 units, enough to get the achievement, in 15 turns, or 14 or 13 in easy mode.
c. I kill 3 Francs Tirreurs units, enough to get the achievement, usually in 6 or 7 turns.

so, why don't I get the complete mission achievement star for completing the mission in less than 15 turns? What is left in the mission?

[AndrewGardner]

It looks like you actually need to destroy all enemy units in 15 turns to get this achievement.