Yeah after I nearly seasoned a salad with wood filler at my uncle's shop, I started putting everything in clear deli containers with big labels. Sounds extra but it beats having plywood flavored potato salad again.

Dealt with the exact same thing on my home set up. Was convinced my grinder was off until I found little white flakes in the portafilter. @michaelw75 talks about technique, and yeah that matters, but scale can TOTALLY mess with your water flow and temperature. A full descale fixed my sour shots overnight. Now I check the machine before I even touch the grind settings.