Hi Sabine. I can’t access your picture, it is missing part of its address. But from your description I think I know what you’re describing. Sometimes when you’re weaving the edgemost (selvedge) threads don’t do as much going up and down as the rest of the threads, and end up slightly longer, and therefore looser. Because they are looser, when you change blocks they get a little sloppy, and kind of pooch out a bit in a loop. If its just small loops then wet finishing will take care of it. But to get rid of it I’d put weights on the selvedge threads back at the warp beam. Hooks with some weight on them (like metal washers) will work. So will paperclips with washers. Anything you can rig up to tighten those edge threads. Then, as you know where the problems will occur, just keep an extra eye on those threads when you change colours at a block change.