I also faced this problem as well.
For CLEAR HLS packaged wtih HE-AAC, the clear version could be played with on my safari v11.1.2.
For HLS FAIRPLAY packaged with HE-AAC, the encrypted version is unable to be played.
The result is similar to your description: the video cannot be started and then stopped immediately. In the browser console showed that the m3u8 and ts are downloaded as usual. I found the https call to FPS server too. In our FPS server, the license is returned as usual.
Since the HLS HE-AAC Clear could be played on the safari, the video files should be no problem.
The issue should be something related to the encryption in transcoder or decryption in Safari.
I've got exactly the same problem with HE-AAC v2. Have you got a resolution from Apple?