This has happened to me too many times to be just chance.
After running Shotcut 18.03.2 for a while, e.g. to export to MP4 a series of projects, the playback of any music in Pulse Audio (11.1-15) running on my Fedora (kernel 4.5.17) is slowed down, just by a little, independently of what software I use, e.g. Rhythmbox or Spotify. E.g. a 3:36 song takes 3:52 to play, that’s a ~7% slower.
Of course, because I am doing encoding and have no GPU, the CPU is maxed out, but can that justify the issue?
Thank you in advance for any insight. Perhaps it’s something we should inform the Pulse Audio maintainers of?