Samsung Tizen app unable to play FLAC – infinite loading, no playback, forces AAC transcoding

[FrostByte 5392]

I don't see anything related to FLAC playback in the release notes but maybe try updating your Emby server (4.9.1.90) and Samsung client (2.2.8) to the latest versions.  And if you really want to go wild DSM 7.3 Update 1 is out.