Graendal had hidden her ability, and inverted her weaves.

We see Leane do this in Knife of Dreams, something any forsaken should be able to do.

“There was something strange, though. More than strange. We couldn’t find the wilder, at first. We couldn’t feel her channeling. There was no glow around her, and we couldn’t see her weaves. The chain just started turning white. If Arebis’s Warder hadn’t spotted the boat, she might have finished and gotten away.”...

“Clever Leane,” Egwene murmured. For an instant, she squeezed her eyes shut. Leane had prepared everything in advance, before coming in sight of the harbor, all inverted and her ability masked. If she herself had been as clever, she likely would have escaped cleanly. But then, hindsight always saw farthest. - Knife of dreams

a second mention in knife of dreams,

"One of them is channelling," Nynaeve said, just loudly enough for him to hear, as she climbed down from her saddle. "I can't see anything, so she's masked her ability and inverted the weave – and I wonder how the Seanchan learned that! – but she's channelling."

And from another passage during the Cleansing of sadin we see that Cadsuane was also using inverted weaves.

and struck instead the inverted shield she had woven, erupting with a deafening roar fifty feet above her head. Even within the shield the air crackled, and her hair stirred and lifted. - Winters Heart

Graendal had hidden her ability, and inverted her weaves.

We see Leane do this in Knife of Dreams, something any forsaken should be able to do.

“There was something strange, though. More than strange. We couldn’t find the wilder, at first. We couldn’t feel her channeling. There was no glow around her, and we couldn’t see her weaves. The chain just started turning white. If Arebis’s Warder hadn’t spotted the boat, she might have finished and gotten away.”...

“Clever Leane,” Egwene murmured. For an instant, she squeezed her eyes shut. Leane had prepared everything in advance, before coming in sight of the harbor, all inverted and her ability masked. If she herself had been as clever, she likely would have escaped cleanly. But then, hindsight always saw farthest. - Knife of dreams

a second mention in knife of dreams,

"One of them is channeling," Nynaeve said, just loudly enough for him to hear, as she climbed down from her saddle. "I can't see anything, so she's masked her ability and inverted the weave – and I wonder how the Seanchan learned that! – but she's channeling."

And from another passage during the Cleansing of Saidin we see that Cadsuane was also using inverted weaves.

and struck instead the inverted shield she had woven, erupting with a deafening roar fifty feet above her head. Even within the shield the air crackled, and her hair stirred and lifted. - Winters Heart

Graendal had hidden her ability, and inverted her weaves.

We see Leane do this in Knife of Dreams, something any forsaken should be able to do.

“There was something strange, though. More than strange. We couldn’t find the wilder, at first. We couldn’t feel her channeling. There was no glow around her, and we couldn’t see her weaves. The chain just started turning white. If Arebis’s Warder hadn’t spotted the boat, she might have finished and gotten away.”...

“Clever Leane,” Egwene murmured. For an instant, she squeezed her eyes shut. Leane had prepared everything in advance, before coming in sight of the harbor, all inverted and her ability masked. If she herself had been as clever, she likely would have escaped cleanly. But then, hindsight always saw farthest. - Knife of dreams

And from another passage during the Cleansing of sadin we see that Cadsuane was also using inverted weaves.

and struck instead the inverted shield she had woven, erupting with a deafening roar fifty feet above her head. Even within the shield the air crackled, and her hair stirred and lifted. - Winters Heart

Graendal had hidden her ability, and inverted her weaves.

We see Leane do this in Knife of Dreams, something any forsaken should be able to do.

“There was something strange, though. More than strange. We couldn’t find the wilder, at first. We couldn’t feel her channeling. There was no glow around her, and we couldn’t see her weaves. The chain just started turning white. If Arebis’s Warder hadn’t spotted the boat, she might have finished and gotten away.”...

“Clever Leane,” Egwene murmured. For an instant, she squeezed her eyes shut. Leane had prepared everything in advance, before coming in sight of the harbor, all inverted and her ability masked. If she herself had been as clever, she likely would have escaped cleanly. But then, hindsight always saw farthest. - Knife of dreams

a second mention in knife of dreams,

"One of them is channelling," Nynaeve said, just loudly enough for him to hear, as she climbed down from her saddle. "I can't see anything, so she's masked her ability and inverted the weave – and I wonder how the Seanchan learned that! – but she's channelling."

And from another passage during the Cleansing of sadin we see that Cadsuane was also using inverted weaves.

and struck instead the inverted shield she had woven, erupting with a deafening roar fifty feet above her head. Even within the shield the air crackled, and her hair stirred and lifted. - Winters Heart