This weekend, I was recording and shooting a cultural event in the which my kids were participating. I had my E-M10 on a tripod recording while I was shooting stills with the E-M1. Everything worked well yesterday, but the recording stopped at about 22minutes/4GB file size (which I expected and was able to restart). Overall, I did about 1.5 hours of video in multiple segments. Today, however, I had only a 12 minute piece to record. The camera stopped recording about 1 minute into the performance and then again 10 minutes into. Both times, it took me a bit to realize that it was not recording and I lost about 30 seconds of the performance each time. Thankfully, there were other people with phones recording and I can splice in the video, but I would like to understand why this happened. The card was a Sandisk Extreme 32GB. Can anyone shed any light on what might have happened? Would definitely like to avoid this in the future.