Beneath this mask there is an idea.....and ideas are bulletproof.
The main SCS rules state that "usually only the terrain of the defender's hex.....affect combat". However on the TEC for 'Day of Days' there is a note against the 'A x 1/2' effect which says "Attackers in Flooded terrain have 1/2 attack strength". So I am assuming this is an exception to the series rules - i.e. the terrain in the Attackers hex has the affect or is this supposed to be the terrain being attacked into (i.e. the defender's hex terrain)?