one question about flanking attack penalty

[eyemooneye]

1.jpg (70.03 KiB) Viewed 6445 times

In this attack toward a stack of HQ divisions, I select two armys in red circle and leave aside two armys in yellow circle, because if I select all, the time stamp will get longer.
but when I check the result of the combat, I discover these two armys in yellow circle are also involved in the combat, as "half-support" as below.

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my question is, when the unselected armys are automatically egaged in the combat as either "half-support" or "block retreat path" in case of fully-surrounding, is the flanking attack penalty valid for them during S/2 or BLK?

regards,