Booklets not always opening straight into a PDF reader

[Uoppi]

I have configured digital booklets using Comment.displayFormat={$*infoFileURI^<a href="^">Digital booklet</a>$comment}

Most of the time this works perfectly and the booklet opens straight into Drive PDF Viewer.

However, after extensive testing, it appears (in BubbleUPnP Android) that whenever there is a "." (dot character) in any of the folder names in the album's folder path (stored on my QNAP NAS running MinimServer), the booklet is downloaded via launching the web browser instead (annoying).

I suppose this must be a BubbleUPnP (or maybe Android?) bug and not related to MinimServer per se?

I could remove all dots from the folder names, if that's needed, but obviously that's not ideal.