Thanks! I left C12 out, but I actually believe I sorted it out, and I am an idiot. Yesterday before posting I switched out the PT2399 in order to rule it out and the second one had the same problem so I assumed all was good.. but today I noticed I could turn one slightly further than the other before it "breaks". I had like 5, so I gave all of 'em a try, I don't know if mine are just particularly bad quality, but I finally found one that works (nearly) the entire turn CW to lower delay time.