Erroneous looping on opening a file

Hi. I’m working through a production tutorial using Cubase 13 pro. At one point I duplicated a section within the project using in-loop select, and duplicate. It worked fine, but now every time I open the project it is stuck looping that duplicate, regardless of whether loop is on/off, or the location of the loop markers. Spent hours working on the project since and discovered that if I press the loop button a couple of times things work as usual. I’ve updated to version 13.0.21 and the problem still persists…