Hildegarde was fully emptied before being mostly refilled. Not sufficient proof we break a seed by skimming it.
It is proof it takes quite a bit to reactivate a witch though.
We didn't just mostly refill Hildegard. We fully emptied Hildegard, then fully refilled her, then skimmed the wings off the top, then Aurora stole some from her. Then we checked her.
I think I get the point you're trying to make, though.
Initially, the discussion was whether reactivation happens when we fill a seed to normal levels. Either it doesn't, or it does but it's possible to deactivate again by skimming. But to additionally suggest that to deactivate a seed that was never broken in the first place requires more than just skimming, that's adding levels of complexity to a simple active/inactive dichotomy that I'm not comfortable with, but neither can I refute.
First, we completely put away the grief before lunch, completely re-filling the seed:
You take a moment to catch your breath, hands on your knees - that was exciting, if nothing else! Finally, you straighten, and look at the dense dome of Grief spheres and the wings visible out of the corner of your eyes. You can't exactly walk around with those floating around, can you.
The only place for you to put the Grief to is back in Hildegard's Seed -you suppose you could make a giant Grief monolith and leave it here, but that's probably a bad idea- so you dig the Seed out of your pocket and hold it up, moving a few spheres out of the way so that the light catches the Seed.
Yep. Still a mostly clear, spherical shape with a pinprick dot of darkness in the centre. You shrug, and begin pouring the Grief back in - it goes in much more readily than it came out, the Seed vacuuming it in almost as fast as you can disincorporate your spheres.
Finally, the Grief is gone, and the Grief Seed back to looking like, well, a Grief Seed. You pocket it, and dismiss your puella magi costume in a blaze of light, fastidiously smoothing down your skirt before wandering out to the main road.
Next, we choose not to form wings and instead drew on our sling bag full to hoverboard to Masami's:
You're definitely going to have to fly out, since wandering the school corridors with your very distinctively not-a-school-uniform clothes is just going to raise more questions. Still, wings or perhaps something new, considering that you did an excellent impression of a drunken moth with said wings?
After a brief debate with yourself that involved a diversion into thoughts about fixed wing flight at some point, you decide to try something new, and hopefully more stable. Under your control, the Grief marbles file out of your sling bag, pushing aside the flap. You mould them into a flat, skateboard sized platform, hovering a few centimeters above the floor.
Then we formed wings as we left Masami's:
Feh. Domestic disputes.
You walk into the alley beside the building and bound to the roof, wincing at the cracks you're still leaving in the walls. Once you reach the roof, you reach for a Grief Seed, and yank a tremendous quantity of Grief out, enough that your wings billow out to the twenty meter wing span. The Grief Seed is still fairly cloudy when you pocket it again.
Afternoon experimentation did not touch the grief in the seed. Aurora stole some grief from Hilde in this time and we then observed Hildegard on the hospital roof:
You reach into your pocket, pulling out Hildegard's Grief Seed to replace the Grief. Looking at it, though... it seems less cloudy than it did a few hours ago. You stare at it, trying to figure out how that happened. Mayb-
Homura's standing in front of you, in the white and purple of her puella magi uniform. Behind her is Mami, similarly resplendent in her own costume, worried frown on her face. The three of you are bound by Mami's ribbons, and the world is hued in the monochromes of timestop.
Homura is busily rifling through your pockets, which you instinctively flinch away from and shove her away. "Hey!"
"Sabrina," Mami begins speaking quickly. "You have a severely overfilled Grief Seed - we could feel it from over there." The blonde points off in the distance.
You blink at her, and plunge your free hand into your pocket, finding the other Grief Seed you have and pulling it out. When you look at it, it is visibly pulsating and surrounded by a sheen of Grief, and now that it's been pointed out - you do notice it, pulsing faintly on your senses.
"Why does this Grief Seed look like that?" Homura asks, pointing at Hildegard's Grief Seed, in its smoky, rather than obsidian black, glory. The black haired girl is frowning at the odd looking Grief Seed - you suppose she would have seen plenty of about-to-hatch Grief Seeds, but this, on the other hand, would be the first half-empty one she's come across.
"I extracted some Grief from it to make my wings," you reply. "Speaking of which, um, let me try something?"
Without waiting for an answer, you hurriedly put Hildegard's Seed aside for a moment, and yank at the Grief in Aurora's. The Grief comes free almost sulkily, heavy, ropy streamers oozing from the Grief Seed. It almost feels like the Witch is trying to hang on to the Grief, but you counter that easily.
You observe Aurora's Grief Seed closely as the Grief flows away - you can feel an impression of the Witch again, the blues and blacks and marble of the Barrier trying to reform - the Witch was definitely trying to hatch again. There's a sensation of... hunger, predation maybe?
Hildegard, by contrast, is simply... quiet, the Grief sitting immobile within the Grief Seed. You wonder, and hope that perhaps it's turning back into a Soul Gem. Maybe, maybe not - nothing seems to be happening right now.
You convert the Grief from Aurora's Grief Seed into marbles, forming a several hundred which you pack neatly away in your sling bag.
Mami visibly relaxes as the Grief Seed returns to a more conventional state, subtle tension of her muscles releasing. "That's amazing, Sabrina," she murmurs.
Homura nods in silent agreement. "Could I have a look at the other Grief Seed?" she asks.