That was my experience, too. I had injection on Aug 7, 2023. Began spotting on Aug 24. Had pelvic sonogram and intervaginal sonogram on Aug 30th and my endometrial lining was at 7. Due to the thickening, I was sent for uterine biopsy. It came back normal. The gynecologist that did the biopsy was aware that steroid injections could cause spotting and did not request a follow-up after the biopsy came back as normal.