Expect another gateway with Daimyo Hermitaur, the first high rank fight. Dude can one shot you in low rank armor! Felyne defender or Divine Whim (the armor skill) helps significantly.
No, you don't even get to hop on. They flinch when you attack them midair and it counts as a mount, but when you touch the ground you won't actually jump on top if you're too far away. So, you'll flinch them for the mount but they get flinched too far away or you go flying off in a different direction because of clipping physics or whatever.
Oh, I see, unsure if I've ever had that happen. I've certainly knocked over a monster with a jumping attack without mounting it, but I'd assumed that was intended. Like you did enough damage to knock them over, but their mounting resist was still too high to proc the mount. Semantics, at any rate!
Just beat that myself, in a set of mostly Rathalos armor (Attack Up L Wheee). And it was...surprisingly easy. I didn't even bring in a second healing palico, I went stealing instead. My biggest suggestion for those having a hard time is to take it
slow. You're given 50 minutes to beat the boss, you don't have to do it in 10. Take your time running around the boss, getting in single whacks and backing off while you get used to his attack patterns. When the monster goes into rage mode, back off again, watch what's changed and adjust. You don't
need to get your full combo off, and a single hit on the monster with no return damage is far more valuable than a full combo that gets you whacked and sends you flying. I honestly spent most of the S.Magala fight running circles around it and pelting it with my Kinsect, getting used to how it worked before I went in fighting.
The
second most useful tip I can give someone is to 'know your weapon.' Each weapon behaves differently, and you'll find your hunting will go a lot easier the more familiar you are with how your weapon works. Watch a video, go on a gathering quest and just spend ten minutes swinging your weapon around to get used to the combos, and when you can stop them for a quick dodge or block. My efficiency went way up when I stopped mashing the buttons and started really working my bugstick.