In the editor:

1. Place player unit and AI, call it e.g. joe
2. In initline of joe type removeAllWeapons joe;
3. Start the mission
4. Run some meters away from joe, then type in debug-console:

joe setSpeedmode "FULL"; joe domove getpos player;

--> If the bug is there, joe won't sprint, but only jog (even though before the introduction of this bug, he sprinted - regardless if unarmed or armed).

BIS - this worked before and was introduced in a stable patch (1.12)!

As with this one here (http://feedback.arma3.com/view.php?id=17699) it has impact on missions where it worked before, resp. significantly limits mission makers.