Board Game Arena

I HAVE PLAYED THIS CARD SEVERAL TIMES BUT I CAN NOT GET THE ATTACH TO WORK AFTER THE FIRST MOVE, BUT BEFORE THE SECOND MOVE, CAN SOMEONE HELP ME UNDERSTAND THIS CARD?

Terrain battle restrictions still apply. It says this on the card. So for example you can't move into a forest and attack, even with Behind Enemy Lines.

THANKS, I MUST HAVE MISUNDERSTOOD THAT PART OF THE CARD BECAUSE IT WORKED YESTERDAY.