Depends what she means by it. It's completely normal for rewrites and reshoots to happen during the filmmaking process, simply because some stuff that works on paper just doesn't translate that well on screen, and sometimes the actors do something on the fly that is better than what was in the script, but that triggers rewrites to accommodate the change.
If Marvel actually didn't have a completed script before the initial shooting began, that would be potentially worrying, but highly unusual.
I'm getting really sick of corporations being held to a different standard to individuals. If I were to accidentally give out non-anonymised client data, I would be facing disciplinary action at least. Until corporations start getting held to account for all of these privacy breaches, they're just going to keep on maximising their own profits at the expense of our data.