Hi Overland,
One thing that can cause a problem is when the wear angle is not vertical enough. However, I looked online at the
diagram of this plane, and the wear looks perfectly fine to me--I would guess 80°-85°. It should work. And it should work with a reasonably fine mouth, say .020"-.030". So, assuming your mouth is not less than 1/64", there are two other places to look.
First is just a technique thing: are you skewing the plane radically, like 30° or more? If so, try reducing the skew to 10° or less, and that will help.
Second, and this is where I bet the problem lies, is the shape of the "nose" of the chipbreaker. A traditional chipbreaker is curved; it makes a steeper angle (around 45°-50°) with the cutting iron right at the tip, but then the angle gets shallower pretty quickly. From the picture, it looks like the chipbreaker just has a single flat bevel, and that bevel looks to be too steep to allow adequate room for the shaving. You can reshape the chipbreaker with a file, grinder, abrasive stuck to a flat surface, or whatever.
When I first started making planes, I made one with an aftermarket blade/chipbreaker (which shall remain nameless) and I had the same problem. Reshaping the nose of the chipbreaker did the trick.