My one of two things is happening
1: Your snake didn't fully get over the RI the first time and it has cropped back up.
2: You have an environmental problem that is making your snake more susceptible to them. I.E. your cooling for breeding; that tub or tank is getting a draft, debris or dust is causing irritation to the air ways. Lots of reasons why they get and keep getting them.
Remember once a Ball python gets an RI they tend to be more prone to get them after.