In a bread a few weeks ago there was a list of units that were deployed to the boarder. The list was made up mostly of engineers, MP's, S1, and S2 types. Some of the engineers units are most likely the ones leaving since they have finished their mission of reinforcing boarder check points and weaknesses in existing sections of the boarder wall. That's not to say all engineers are leaving as missions are unit specific.
Morale is one of the largest force multipliers.
indeed
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