While testing JDK-8232589, I noticed following issue with was reproduced with JavaFX 8u231 and OpenJFX 14, so I think this issues exists long time ago.

Force media player to use OSXPlatform only by specifying -Djfxmedia.platforms=OSXPlatform

Run application FXMediaPlayer (can be provided by request), open any media file (mp3 will work) and hit play. Enable loop (cycle count set to infinite). Playback will loop only once and on second run it will play to the end, but never sends EOS and loop again.