... Has anyone confirmed this claim? Is it in S1 or Reaper or Standalone or all three?
YES affirmative
... It was replaced with v3.9.12 which fixed this problem. But I already told you that!
I gave the users 3.9.9 as it used a earlier version of bbw4 before it rendered to 32bit:
I installed 3.72 and the popping problem disappeared
But an error pop-up appears. Cause all programs to close
I followed 3.99 and the pop problem disappeared
But extra and riffs cannot be used
I tried it in 1.4.2 and there was no noise, I loaded 3.9.12 on another track and there was noise !
You maybe using USB ASIO device, try it with another audio device or on-board audio.