OK .. i did some looking. Here's the deal:

In the old code (i.e. pre 41), there was an object that represented a node and it's parent together. After a substantial rewrite, that object disappeared (replaced with something else). That object provided the context of what node you are downloading and its parent playlist (i.e. for pos translation). In the midst of those code changes, the method that parses those filename strings never got upgraded to take the new object, so it doesn't ever get the playlist context passed in... I'll fix this in the next release.

Mike