When using Canon 6D, with one YN-622C II placed on camera. And the other YN-622C II placed on a cold shoe mount externally and 600EX-RT Flash placed on top of that. The flash fires inconsistently or not at all.
I have to jimmy, fiddle and fool with the 2nd YN-622C II that is on the cold shoe mount to get it to fire. It seems that the "prongs" that are at the base of the transceiver might be the problem. When they are "pushed in" due to being placed on the cold shoe, it causes the flash to pop crazily on it's own, then not work at all.
I have checked and the channels are correct. It ONLY doesn't work properly when placed on the cold shoe. It DOES work when the flash is only placed on the transceiver and hand held. Do I need a different shoe mount? I need more knowledge of this.
Below are the items in question:
Bracket with adjustable shoe: https://www.bhphotovideo.com/c/product/656152-REG/Impact_9101880_Umbrella_Bracket_with_Adjustable.html