I position appropriately qualified units to besiege a fort and at the commencement of the following turn am greeted with a symbol announcing that the fort's defences now offer no protection - most gratifying. I maintain the siege only to find that at the commencement of the following turn the said symbol has disappeared - less than gratifying and most confusing. Are the defenders still unprotected, have they rebuilt their defences, was it all a cunning deception? Lord, it surpasseth all understanding.
Can someone unsurpasseth it for me, please?