I had several attacks planned on two fronts. So it is really two separate issues.
First off the armies of the defender have been exposed due to espionage.
The AI split 11 infantry troops, sending nine to attack by sea. They most certainly did not have 20 infantry in that location. I had waited and moved to counter attack with six infantry when they began disembarking. The assault left me with two infantry which I sent back to the city following the attack.
When I restarted the game, there were 11 infantry back at the original city and the remaining two of my own. No screen shots prior, apologies.
Second question, is it possible for an infantry attack, one attacking troop and 6 defenders to have a null outcome? No losses on either side?