Okay.
6.17: Nothing. Why did you start here, it's arbitrary as fuck.
6.18: Fixed a bug where the slow on her Q didn't last 2 seconds at all ranks. Technically a buff, but it was supposed to have happened 5 patches prior.
6.22: Restored her running animation on all skins (the fuck does that even mean) and made Winter Wonder Lulu's Pix VFX snowy again.
7.2: Made it so that Lulu actually uses her running animation when she's supposed to, rather than walking really fast, changed Pix's damage to 15-117(based on level) from 9-105(based on level) and took 10 off the mana cost of her Q at all levels, bringing it to 50/55/60/65/70 from 60/65/70/75/80.
7.3: Made targets polymorphed by Star Guardian Lulu display their champion name as Blob.
You're right, that change in 6.22 totally broke her.