I was out with a rented (nearly brand new, I believe) Epic-M this past weekend and had some pretty significant issues with the latest release build firmware (1.7.10)
Twice when I switched to 4kHD mode, the camera froze up and would not boot. It seemed like it froze while switching modes and then when booting it would freeze while booting. On boot it would show the chip chart on the EVF but never showed anything on the touchscreen. The only way to fix this was to reinstall the firmware. After this happening twice in 1.7.10, I went to the previous release build. I also did not go to 4kHD mode again in the older firmware as I was on a job and wanted to avoid any chance of the camera freezing up.
Has anyone else seen this issue? It's bad enough rental cameras usually only come with release builds that are still missing many features (playback, 3k, etc) but to not have new features AND still have huge bugs like that is pretty frustrating.