Does a cloaked unit loose cloaking and concealment if it attempts to move into a brush hex occupied by a HIP squad in a trench?
An infantry/non-charging cavalry unit/stack that attempts to enter a Location containing a concealed enemy unit/stack invokes A12.15 (in general; see also G.4, and cases such as berserk, human wave, bypass, etc.). The moving stack is bumped back to its previous Location and at least one defender unit loses its concealment. HIP for the defender and cloak for the moving unit are just forms of concealment. The trench is not revealed at night as the enemy unit did not truly enter the Location [E1.16].
If the defender had been a halfsquad the attacker might have invoked HS infantry OVR [W7.6], but that's not the case here.
JR