Yep. Sounds familiar. Once my family owned employer turned towards a more corporate model, they brought in people and one of the first things they did was limit the time that email could be kept.
We asked why? We had plenty of space and system capacity. They said bluntly "to limit liability". I.e., can't provide damaging evidence to the person(s) suing them if it's corporate policy to delete all email after X days.
I can't count the number of people I worked with that set up rules to auto-forward all emails to a private gmail account to cover their assets as soon as that came up.
Another tactic is to ask you something verbally, so there's no digital record of it being asked. So I'd send the person asking an email, and state "per our conversation" or "per your request" here's the info that you requested of me and bcc a copy off to gmail.
Of course, these weren't trade secrets or anything like that. Just people trying to make you complicit in dubious behavior.