I have started to use my V6iis transmitters and RF60s daily, and I've started to see something with shutter speeds on my A7Rii with the kit.
After about an hour of shooting, if I move from a shutter speed of 1/250 or lower then move up to a shutter speed of over 1/1000, I'll see the RF60s go out of sync and start to produce lines on my shots.
I am only about 6 feet away from the flashes and transmitters, and have tried both the short and long transmitter power.
The way to get them to sync back is to just reset the entire system. That takes time and looks shoddy when my subject is on my clock!
This was a very bad thing to see happen and caused me much pain because I had already started to use them with confidence. I am going to have to reshoot two sessions, and that is costing me some serious time and expense.
EDITED: I'm trying to figure out why this intermittent problem happens. Lots of trial and error. It sometimes happens when I set it on 1/1000. I took the F32M out of the picture too, but i still see the problems.