It's not uncommon, as removing the colon may not immediately address other areas of inflammation. In fact, I suffered most of my intraintestinal manifestations AFTER most of my colon was removed. I still had the rectum and my UC there never went into remission, but after my subtotal colectomy, I developed a retinal inflammation and later on, severe mouth ulcerations (not just the common tongue ulcers; this was all over my gums and I had difficulty eating). I was also worried about Crohn's, particularly with the mouth ulcers. However, I'm happy to say that once my rectum was finally removed, the other issues resolved.
You are still close out from your surgery so it's very possible that some of the other areas haven't settled down yet. This is particularly true if you are just tapering down off prednisone or other meds. The other issues may have been kept in check by the steroids, but may be noticeable as you lower the dose. You may therefore need to stay on them for a little while longer until your entire system calms down.