Batch rename using wrong date (691231)

For years, I have batch renamed files in the format: text_capture date_text_0001.JPG and batch moved those into a dedicated folder. Recently, rather that the capture date, it produces: text_691231_text_0001.JPG and moves the incorrectly renamed files into individual folders corresponding with the capture date and not into the target folder. Someone suggested the date 691231 might have significance as the day before the unix time code started. Any help greatly appreciated.