Flexible air can be changed by customers up to 45 days prior. Which is when Princess traditionally paid for the tickets. As I learned with two experiences post-pause, they haven't been paying the airlines until closer to 30 days out. And of course for some they've simply fallen into the cracks and not been paid at all.
I had listened in on a call with TAs a while back (I'm not a TA by the way) and Princess acknowledged EZAir issues. They said they were beefing up staff in that area. And they also said that they had the same number of staff responsible for air as there were prior to the pandemic but it's not enough due to all of the airline changes. Whether that is true or not is anyone's guess. But it's unacceptable that these sorts of issues keep happening.