Incorrect Track Number being passed to control point

[simbun]

It seems that if I have a multi-disc album the track numbers are incorrectly passed to the control point.
I chose my contentDir to point to a single album, and when I have a single disc (discnumber = 1) the track numbers displayed correctly in BubbleUPnP, however if I change the disc number of the last x tracks to 2 the track numbers are skewed.
I made sure it wasn't because I pad the track and disc numbers and it still failed.

My example:
A single album with track numbers 1 to 15 and a disc number of 1, displays correctly e.g. [01. track name] to track [15. track name].
If I change the last 6 tracks to disc number 2 and rescan, I see tracks 1-9 and then 19-24. There's no mention of these track numbers from the writeAllTags log, and I can see them being sent through the MinimServer Trace logging.

I've uninstalled MinimServer and removed the previous config just in case something was corrupted, and am using Windows 0.8.5.2 update 128.