Hmmm...I have a new block of
Clay Magic I have not tried yet. But I have been using car soap (Mother's) as a lube for my Mother's clay bar for quite a while and never had this problem.
Did you throw that bar away? I am wondering if it will get back to normal after it dries out for a bit. I don't know what the composition of detailing clay is, but being a geologist, I know that with clay in soil, if it's overworked and saturated, sometimes the cohesion breaks down, but will reform normally after the moisture evaporates. Might be worth a try.