Man this is perplexing me. Iwata HP-CS. Had some intermittent spray issues and a few bubble in the cup. I figured I needed a better seal. Took it apart, soak stuff in restorer and added some (harder than I would like) Bee's wax to the threads. Now it's worse! Now even if I just depress for air I get massive bubble into the cup. Took it apart, figured air was getting blown back somewhere. looked with a loupe and the main airhole is clear, the 3 holes appear clear, all the holes appear clear. I cleaned the threads and tried sealing it with softer chapstick. Same issue, no change. So, why bubble with just air alone not even pulling back the trigger (like it was before I tried to "fix" it)? What should I be looking at or for? I even sprayed some water around the threads (yeah should have been soapy water) and didn't see any obvious leaks. I'm obviously missing something.