I think you’ve misunderstood me Hudson555x, though I do appreciate your efforts to be of assistance.
Whilst I am actively using Shotcut there is no waveform visible, however when I leave the PC or the software unattended the waveform is visible on my return. The hardware I’m using is a combo of storage - SSD for software & HD for storage. When I load a project and work on it, no waveform shows, no matter how long I am working. If I leave the software unattended it eventually becomes visible. The screengrab below is taken from the exact same spot as above but 75 mins later (I deliberately did not touch Shotcut in that time to see if the same would happen as yesterday), during which time the PC was in use on other tasks. The PC had also been in use on other tasks for 2 hrs PRIOR to the screenshots in the previous posts. During all that time the processors and SSD/HDs were kept active since I was working on sound files, vector gfx and script with frequent saves
I have been using Shotcut since the end of 2017 and this behaviour has not been present on previous versions, only since 18.05.03. I am confident it is neither because I do not know how to scroll down through tracks or that my HD is spinning down. Clearly it is not affecting everyone but it is hitting some of us as the OP and others demonstrate. Bug reports help the Devs of this brilliant piece of software make it better and suggesting that people reporting said bugs are unaware of basic PC operation could be counterproductive.