Usually disappearing lather is the result of not enough product on the brush. Sometimes it's just the product itself. Playing with water ratios until you find the sweet spot is always advisable whenever you get a new product.
I'm glad you got it. It usually takes most people a while to get the whole lathering thing down pat. You can get a usable lather easily enough but to get a really great lather consistently takes a little deliberate practice. I think a lot of newbies don't bother to practice simply because they have no frame of reference by which to compare their results.
TOFLAC-U, AOM, LEMS/ Stay back! I have a Merkur, and I know how to use it!