Intermittent 3D issues

I tried watching a 3D film for the first time this week on OSMC (latest update) on Raspberry Pi2. The TV is a Samsung which auto detects 3D. Mainly it worked well, but at random intervals, it would change to a black screen, switch to 2D (I could see for a split second the 2 images side by side), and then switch back to 3D.

This kept happening intermittently - sometimes it could go for 20 minutes without any problems, and other times it would do this 3/4 times in less than a minute.

Any ideas how I can troubleshoot this?