PS4 Plex not responsive and Plex says buffering with H.265 and AC3

I have a file that is H.265 and has an AAC 7.1 and AC3 5.1 audio track

The AAC7.1 and H.265 play within seconds of hitting play and the H.265 is transcoded to H.264 and AAC7.1 to 5.1

Now if I select the AC3 audio. I get plex says buffering and it is transcoding H.265 to H.264 and says it is direct streaming to the PS4. No it is not processor issue as my server only running at 35% occupied while transcoding and it can transcode both video and audio with AAC just fine.

I copied the audio track to a standalone file vlc plays it no issues and MediaInfo correctly identifies it.

Any suggestions on how to troubleshoot? Has anyone seen this?