Plot expedience makes all of us clumsy sometimes.

Velma syndrome, strikes when you least expect it to.
also a vaguely recall her tripping again in a later ark.

Imagine if she had to look for a contact lens after a fight.

It's a character trait. She's explicitly clumsy.

I half expected that and her near-blindness to be in-game flaws to explain why she's almost as strong as Zoro.

Uneven street stones? Her own poorly made shoes? A puddle of dog piss? Straight up natural loss of balance? I nearly trip over 'nothing' all the time. Mind you I am generally just a klutz and am not a super swords-woman able to take down two guys in one strike. Or even two strikes. Or probably at all.

She slipped on the gallons of blood spewing from their still writhing severed limbs. But they censored it out.

Invisible blood huh, is that more in demand than invisible guns or less in demand? I guess they might need to use visible blood for nosebleeds here... I don't know.

They are saving the visible blood for when Sanji gets to Fishman Island.

I think that the implication is that she's just clumsy.

Think about it. She’s out in the middle of the Grand Line with some pirates she barely knows. She looks around her, what does she see? Nothing but initiative rolls. “Oh, they're attacking me, what am I gonna do, not trip?” If there's nothing on the ground, then she obviously isn't gonna trip. The thing is that she’s gonna trip on SOMETHING, she’d never not trip on nothing...because of the implication!

I am tripping over even ground almost every day at least once.
There is nothing wrong with this scene.

That's totaly some kind of Flaw that make her very unbalanced.

That aside, she is looking around her, maybe she turned her heel the wrong angle and tripped. or alternatively, since the ground is paved, she might have tripped on the edge of a slightly surelevated slab, or a thin crack between two slabs.

A Flaw?! "clumsy glasses girl cuteness" should be a feat that grant her a +4 bonus on diplomacy check through the sheer charm of the combination of glassses and clumsiness.

"If you can't turn the Flaw into a mindbreaking benefit in the weirdest way, you aren't being Munchkin enough."

Speaking of taking advantage of flaws. I used to play an online game where literally everyone was blind. This was because blindsight was easy to get and a few attacks targeted only people who could see them. As such everyone purposefully drank poison to blind themselves and then just ignored the disadvantage with blindsight.

Please, tell me someone made a character who was basicaly daredevil.

Funily enough, it remind me of something a while ago.
The GM was the kind who would not hesitate to put the party in perillous situation, but on the other hand tend to go with wathever was the funniest. he also described the npc with a few cosmetic details to give life to the game (or hide crucial clues in plain sight when we are not paying attention to the description), and sometime one of theses details was that a character had glasses.
Rather early on the campaign, there was a recurring NPC who was trying to court a Lady, who happened to wear glasses, he was a con man after her familial riches and we had to stop him, simple, we did it, and no one was accidentally killed in the process. Later in the campaign, we came across this guy again, and he was trying to redeem himself, so that he could settle with a woman he loved, and she also happen to wear glasses. We doubted his sincerity, and ended up ruining his chance with this girl, and he deeply ressented us for this (and the fact that we accidentaly burned his house later).
Then even later, we saw him again this time involved with another lady (it was long after the previous occurence), and one of us jokingly asked "did she wear glasses, too? this guy clearly have a glasses fetish, so she should." the GM was "sure, why not". and so it was admitted that this guy had a glasses fetish.
Then later in the campaign, our mage lost part of her eyesight, in a incident involving a few bad roll, a character losing a hand, and a plan that backfired badly, We suggested that she should just get glasses, and managed to negociate that since there where a few NPC with glasses, it meant that there was a relatively good ophtalmology in the country. One trip to the optician later, we had a glasses wearing mage in the group.
Later we saw the NPC now known to us as "the guy with the glasses fetish" (still in a relationship with the lady of our previous meeting), and we needed his help. Problem, he still did'nt liked us and barely trusted us. we tried a bit of diplomacy, and the mage pointed out "Hey, since he have a thing for glasses, do it get better chance than the others?", and it worked !
the moral of this story is : my stories alwways end up longer to tell than i thought.

I'm sure this can be made to work.

Maybe is a Minus? She have to many pros, so she must have added some weakness, one of them just like Zoro can't find how to go, she trip everywhere

I don't know if it was just the animation studio they were using at the time, but I always find it odd how thick Zoro's eyebrows are in the East Blue Saga compared to later on.

If you watch the scene very carefully, you can see that she just straight-up trips over her own foot.