Hi there, Bought my GH4 in september and had the same issue here in France. My operator did plug a cable for monitoring, but after that we couldn't plug anything else. So we thought we damaged the port. I had it returned to "La Fnac" which is sort of BH in France, and they sent it back to me (I think it went through Pana), claiming it was ok. Didn't have the need for hdmi output in a while, until last month, then I discovered the problem was still here ! So I went back to "La Fnac", and asked the guy to try his own micro hdmi cable, as mine (amazon cable) could be faulty. He couldn't plug it.