I found it... -__- I don't recall ever changing it, but it is fixed. That's exactly what is was too, Mr. Magic. I just figured it out right before seeing your post lol.

Somehow in Character Configuration, under General tab, and the section for Flying Mount Takeoff it had switched from the Auto: Take off on jump over to Manual: Take off on double jump. It's literally in the character config, I'm just confused how it changed. xD I must have.. accidentally clicked it when changing another setting and saved without realizing it?? I didn't even know that was an option, after a couple years of playing the game!

Thank you for the response! I'm glad it was such a simple fix, I just missed it the first time I was going through my character settings cause I never noticed it was in that weird spot. I kept checking my keybinds thinking I messed something up in there lol.