What's wrong with Feint?

One of my Primus gladiators - Murmillo, a 2H War (a Master of Arms actually but I don't have the money to change his weapon at will as I would like to) - has his training completed for maybe 2-3 months now. He has Feint and Hamstring both at 10 where Hamstring was trained to 10 points first and Feint after it. Right after Feint reached 10 points, he almost completely stopped using Hamstring. For the last few months he has hamstrung someone literally 4 or 5 times out of... I don't know, maybe 500 combats or more. At the same time, he uses Feint for almost all of his attacks. No other "active" skills in the list, just these two.
I like Feint but a War without Hamstring is half as effective as he/she could be otherwise. Anybody has an idea why this is happening this way? I don't think it's related to the attributes as he has much better Strength-Intellect combo (Hamstring) than Intellect-Agility (Feint). Other thoughts?