Text Thread is off the artboard/page?

My document has threaded copy throughout. There was overset text on the last page, when I went to create another textbox to link it, it automatically threaded to something off the page (indicated by red line). I thought maybe there is a hidden text frame but have not found anything. I also used the breaking thread script, but that didn't work. I replaced the text frame and still nothing. I selected all on the page, got nothing. I even cleared out object styles, and paragraph styles, but it still keeps threading outside of the artboard. Please help!