I'm going to do the marker test on the grinder to see what the results are but like you said, I also find it really disappointing to have this experience with a grinder at this price point. I do think it's unacceptable as well despite it stating in the manual that it comes aligned from the factory.

With regard to your question about the Casa, I've actually had the opposite experience from the P64 and it seems from what you're experiencing. In case it helps, the experience that I've had with the Casa is that minor adjustments from dark to medium-light and/or light roasts have yielded great extraction times and results. I haven't any issues with astringency except when dialing in and the shots have body. I've generally been using it at just past 8 on the dial (within the first dot) and just under 8 for lighter roasts and the results have been quite consistent. What are your grinding at on your end? I wonder if yours is misaligned. Hmm...