Tags retrieval fails for netstreams with undefined length and custom filesystem

As per title: tags retrieval don’t seem to work for me when playing netstream e.g. http://ice1.somafm.com/spacestation-128-mp3 which is being retrieved separately and provided to FMOD via custom filesystem
[ sound.getNumTags returns 0 and sound.getTag FMOD_ERR_TAGNOTFOUND all the time]

Tags do work, however, when a finite size file is played from a network location - using the same code/custom filesystem

The only practical difference seems to be setting filesize to retrieved content length or being undefined (uint.MaxValue) in opening callback
Is this something which might be causing this behaviour ?
(the sound plays without problems otherwise, i.e. no stutters when loading/playing)

Thank you