It's just a baseless rumor as far as I can see. SW says there's a staffing problem at "one location in florida," and blames weather otherwise. Meanwhile at least the SW pilot's union says "our pilots are not participating in any official or unofficial job actions." Union goes on to say the disruption is because of SW's "bad management."
Given that the people who are ostensibly striking have yet to say anything, I think that no one is striking or walking out.
edit: this is as close to a source as I've seen for the claim that there's striking workers: https://twitter.com/jackposobiec/status/1447259256001019906