I purchased a pre-wound warp for tea towels. I noticed that some of the threads in the loop at the cross end were cut. I'm used to threading my apron rod through the loop. The seller told me she wound the warp on a warping mill and it is not continuous as there were colour changes. Is this normal? If I can't thread my apron rod through the loop, how do I attach the warp to the apron rod at the back of my loom?