From what I've read, the call-out rates for the days where issues were occurring weren't abnormally high. I don't remember as many details about the AA cancellations, but I know with the Southwest/WN ones both the union and the company were saying that call-out rates weren't higher than normal. If there was a major action happening, I would think that we'd see that number go up, and it'd be used as a semi-official talking point, either by the company as a way to deflect blame, or by the union to show that they mean business.
There might have been a few that called out over the mandate those weekends, but everything points to more fundamental issues, particularly very tight staffing and trying to run 90ish% of the 2019 schedule with 75ish% of the 2019 staffing numbers (I don't recall exact percentages, but the general proportion is correct from my understanding.) When staffing is that tight, minor delays can quickly cascade into catastrophic failures. Add in overworked staff who may not be as willing to pick up an extra shift to help get things back to normal (particularly over Halloween weekend when many have other plans) and it's harder to pick up the pieces and get things back to normal.
Note: I don't have any inside knowledge so all of this is just what I've read/heard.