Read the label? Check first ingredient, sounds a lot like you're using the palm oil version.
I read the label and it's definitely a tallow version. I tried it again yesterday and although I got a reasonably usable lather from it, it irritated my skin. I had the same problem when I used the Erasmic before but I wasn't able to isolate the cause until now.
I'm going to stick with the Palmolive as my main soap.