I was replaying the game again an I don't remember the Mahir fight being as tedious last time. I don't even recall the "Dazed" state ever activating in that fight. Now it's been happening so much that it feels unwinnable without several restarts. Was that always normal?

The short answer is that nothing has changed in GT since the last update, and I haven't touched the Mahir fight in much, much longer than that (aside from updating the fight music). 

The longer answer goes like this: The Mahir fight, like a lot of my boss fights, has a "gimmick" to it. It is possible to win the fight without using the gimmick, but normally this should be very tedious, which should in turn cause the player to wonder if there's a better way. However, due to rng sometimes people just get fairly lucky and win without gimmick or tediousness. That's probably what happened to you the first time. 

The gimmick for Mahir is that he has "fake" attacks: you have to pay close attention to the icons during the windup. There are also other tells if I remember right. You have to figure this out and use this information to attack when he winds up one of the fake ones. This becomes more tricky because, again, if I remember right, the fake ones are only fake IF YOU CALL HIS BLUFF. If he winds up a fake one, and you attack INTO it, it will never land. But if you DON'T, if you just defend, it WILL attack, so you'll be stuck defending for ages and doing almost no damage.