It's weird that it has been in both directions, with some accounts losing large numbers of followers but others making sudden large gains.

The reports I’ve seen on this implied that (in general) left-leaning accounts were losing followers, while right-leaning accounts were gaining them.

Given that the coverage we’ve seen in various quarters (where the left generally fall into the “Elon buying Twitter is bad” camp and the right fall into the “good” camp), the changes in follower counts seem to be easily explained by a rash of rage-quitting left-wingers and a corresponding rush of right-wing Gab/Parler users giving Twitter another chance.

It could explain it, but it could also be something else. Without twitter disclosing there's no way to know.