I noticed the same. I face lather and before the first pass, I only need just a couple of swirls on the soap (MWF) with a fairly soaked brush and there I go, nice lather builds. But on the second pass, it deteriorates. And on the third pass, no matter what I do - more water/more product/wet the face/wet the brush and all the possible combinations - I can't build the same quality lather (on the face or in the scuttle) that I could before the first pass.

I'm experimenting with face lathering (with MWF only since it is the only soap that I have) because I just hate when I build too much or too little in the scuttle.