A sad tale
Never, EVER, use a yarn like this one to make a warp. It is two strands twisted together and all it wants to do is twist round itself and make a big knot. I have done the most dreadful thing possible when dressing the loom, short of cutting the shafts into matchsticks with a chainsaw.
I HAVE LOST THE CROSS.
Sounds like a spiritual breakdown, but it is far worse than that. I may have to abandon this warp altogether, although it is only the middle section of the warp that is affected. This is the salvaged remainder of the mighty big long warp I messed up last year and it looks like it is just a bad, bad, bad lot. I will carry on threading up and see what happens when I try to weave and wind on. If it is too much trouble I will have to abandon the project and file it under "experience".