I'm going by Rob's response when someone listed it as a possible blooper:
We know that she shifted back to an Ansom-unit schedule after being released (unless you think that Webinar would have not noticed, or seen anything suspicious about, her having rations pop at dawn). That's consistent with it being a result of being held captive (she was no longer a prisoner, so she shifted back to her own side's schedule), but not consistent with it being a result of having been converted to Stanley's side (she was still under Wanda's spell).
He definitely did know that Wanda had some sort of control; she explained that (except for the parts that were just too "complex" to go into) during the planning session for the aborted ambush scheme. Parson later references the issue in his Klog:
It seems that he is doomed to disappointment on that score.Dwagons ready to strike, but we probably lost our chance and gave up the prisoner.
She better be a good mole so we can win the big battle, then.