Playback speed increase after seeking

It seems when repeatedly seeking (using the time bar to go to certain times), the speed of the playback increases (not by much, less than a 2% increase). I originally thought I was imagining things but I found some evidence. I have a audio file and sheet music (MIDI) for that audio file. The sheet music says to play at 64 BPM. I started playing both files at the same time and I found I had to increase the speed of the playback of the MIDI file to 65 BPM to keep up.

Although the speed increase is barely noticeable, the pitch increase is. Triggering this bug by seeking seems to work 99% of the time (sometimes it's hard to hear that pitch increase). In addition, repeating the process seems to accumulate the effect of this bug.

Although this bug may not sound good to the ears, it's easily resolved by pressing stop. But, going to a specific position, whether sliding the time bar or using "Jump to specific time", this bug happens. This bug has been present for a while, since I started to use VLC Media Player about 1-2 years ago.

The attached video provides the evidence. I started playing the audio file and the MIDI file (not shown on-screen) at about the same time (it's a bit out of sync) but towards the end, it's clear that one is ahead of the other (it may be easier to distinguish the lack of sync when the chords are played).

Video link: http://youtu.be/Wc7KSwTqsaA Thanks guys, I can't fit 3 minutes of video in 500 KB to upload here.