I agree a huge swing in your out-of-office bounces is something to warrant investigation.
I did take a look at about a dozen of your most recently campaigns and saw a consistent 35-40 out-of-office bounces noted.
I did check with the deliverability team and they said these bounces can vary from each email client. Some email clients will bounce back an out-of-office message to us that our system identifies and labels correctly but other email clients do not.
In mentioning you were seeing a swing of up to 200, the team asked that you call in so they could troubleshoot further.