Tested this some more and I'm afraid the issue still persists, just under different conditions now.
On this link is a gif demonstrating the weird progress bar behaviour when a soundcloud song is played.
In the video, I played a song to which I proceeded to seek/jump to two different points in the track and the progress bar started doing its thing.
On the 'first jump', MB successfully played the correct portion of the track. But on the 'second jump', it wasn't playing a part of the song I expected it to.
