Here's the thing, that happened and it will continue to happen (fortunely or not) simply because it fits Jason's character well, he's a brawler amoung other things...he was never intended to be a great martial artist, its not who he is.
People love when some writters make their characters look as awesome as possible, even when what they do doesn't fit the character thei're writting...and they ignore or forget, that that stuff will be eventually ignored by future writters who will writte that said character accordingly.
Stuff like this happens al of the time (ex: even Batman himself was once stated as being a master of all fighting forms, and having mastered all nerve-strikes, and yet in the majority of his appearences he doesn't show this level of skill, even in some of his best fighting-showings he wasn't portrayed as being this good, because he isn't! he had it for those stories, but the writters before and after ignored it...you have Bruce being shown at being in the pinacle of human condition on his training, stallemating top-tier-fighters like Richard Dragon, Lady Shiva, Bronze Tiger, etc, and then you have thousands of showings where he is portrayed as being a "good" fighter, but not extrimely good)...(another ex: Tim Drake was always intended to be the smartest amoung the kids, but then some writters wrote him as incredibly skilled fighter, they even showcase his focus in the field and everything, which all amounted to nothing, the writters that came after ignored it, you have Tim beating Shiva in a training session, and then you having him losing fights to Damian, Dick Grayson, Jason Todd, etc, because he was never supposed to have that level of fighting skill and for all events and purposes he doesn't have it, as its shown by the large majority of his showings.
Jason Todd fans got so happy when he beat Shiva, and forgot that stuff like that gets ignored real easy...since flashpoint he has beaten Shiva, but he has also, lost to Damian, Barbara Gordon, Cheshire, Bane, possibly harper although it was off-panel, and the list goes on...Now, am i crazy, or all of those people should lose to Shiva? if so, Jason is not that good, only in Loebs mind.
In the battle threads, we have a reasoning, that we should ignore all of the inconsistent showings, for that exact reason.