Hi DannR and thanks for supporting the product. 😀
I have the same issue (on a BMW iDrive). The files which were originally FLAC play fine the AIFF flies converted to FLAC just stay at 0:00:00 until they error and go to the next converted file which does the same, until they get to a file that was originally a FLAC file, which then play.
The FLAC output options are set at "Match Source" and the original AIFF Flies have a sample rate of 44.1kHz. What are you suggesting in terms of changing the sample rate exactly? Happy to test options.
Thanks again