Here’s my WAG. Are you careful to rinse the soap off the washcloth before you put them in the wash. I know that there is some reaction between soap and detergent and that might be the cause. It does not happen to me, but I try to rinse the washcloth carefully before washing it.
Cloth fibers tangle when washed, creating a stiff cross-stiffened structure.
You fix this by flexing the cloth, to tear the tangles loose: you avoid it by flexing during drying, to tear the tangles loose.
People who hang cloth out to dry in calm weather find that the cloth is stiff when they take it in: I live in a naturally windy area, and my towels are soft when brought in. My washcloths are not always soft when brought in, because unless it is fairly windy, they don’t catch enough breeze to flex.
[Moderating]
Let’s cut all of the semen jokes, all of you, right now. As well as the erection jokes and any other sort of sexual jokes you might think up.
No offense but, you’re about 38 months late to those comments.