This is apparently an existing policy from Twitter, as The Intercept discovered after they posted their article:

This article was updated to include information about a Twitter policy to temporarily remove checkmarks from verified accounts that change their profile pictures. Twitter offered only an auto-response to The Intercept’s request for comment ahead of publication. The article was previously updated to note that Twitter restored UAW’s Twitter verification after publication.

Musk is an asshat, but it sounds like this is existing Twitter policy.