I have a similar problem. Had DSayers OpenATV 6.2. Upgraded it to latest version and got cams from softcam-feed-universal_4.3-r4_all.ipk (stuck it on a USB and installed it via plugin installer)
Noticing this problem with Mgcamd 1.45 as well.
Tried Oscam-emu, stable and trunk (all 3), but problem still persists.
For me if i turn off the box (zgemma h2h) and restart it then its all blank.
I need to restart softcam/switch to mgcamd and then come back to
Oscam-emu/stable to see which one works (Oscam stable 11572 and Oscam-emu r11576-798)
Provider said might be a build issue, so went from OpenATV 6.2 to 6.3 and 6.4 (fresh upgrade, no backups or plugins), but same problem across all builds and with all versions of Oscam and seems to be now affecting Mgcamd. Is there another source of cams out there. I have tried the one's that show up in the plugins menu and no joy.