Panasonic V10 - picture drop outs

Good evening everyone. I appreciate this would normally appear in the owner's thread but as that is now old I thought I should try my look here. I have the 50" V10 and when I change channels on my Humax HDR or esp when viewing menus or using the red button the picture often flickers or drops out. Sometimes the screen displays the aspect ratio in white 16:9 in the top left-hand corner. This can get annoying when it happens regularly. Thankfully this is relatively rare. I also notice it when switching between SD and HD. Everything is connected via HDMI and goes through my Denon 1910 cinema amp. Has anyone else had a similar issue. Thanks for reading. P.S. I should add that sometimes when changing channel or resolution green noise flashes up on the screen for a fraction of a second.