Comment 9 for bug 1130920

Sorry for misunderstanding, I thought that question was about Ubuntu installation. Openshot was installed from Ubuntu repos, not from usb stick.

Anyway, I managed to solve the problem. It was because of melt/libmlt, I had the same issue in kdenlive.
melt was unable to correctly process "Audio: pcm_u8, 11024 Hz, 1 channels, u8, 88 kb/s" audio format.
I converted the sound stream for all videos it to "pcm_s16le, 22050 Hz, 1 channels, s16, 352 kb/s" and glitches are gone!