Okay so my Support Request on this issue was marked as Solved this morning, without any explanation, and the ticket has been completely closed (comments no longer allowed).
Obviously the issue is still there as 12.0.30.
To me this is quite disrespectful. I spend hours everyday on this forum trying to find bugs, testing them thoroughly, then sending support tickets, and this is the result.
Edit : I also mentioned the “thick silence lines” issue in a separate ticket in which I explain the whole problem about Smooth Waveform Drawing (here on the forum).
This ticket last activity is from this morning too, so I guess the same person is currently investigating it, since it is still opened, though there is no comment yet.
Wait and see 