Metal Gear Solid: Peace Walker - ULUS10509

[Herrod22]

I can't complete Mission 24, I'm on the last map, I shot down the chopper and then killed the four soldiers which came out of the exit.
Normally you should be able to exit the map once you killed the last four soldiers, but the game doesn't recognize it and says I have to kill all soldiers before continuing even though I already did so. Happens on all versions.