It appears to be an issue with nicehash control -- I have this issue with any CCminer 1.1, 1.2, and the latest NVMiner build.
Behavior only present on auto-switching.
The behavior is present across multiple rigs (780 rigs, 750ti rigs). Running the miner with a built in pause command does not change the behavior either.
Again, it still generates shares, but they are either not submitted to my deposit address, or it is running in benchmark mode.
It's typical fast-ccminer-switching behavior. There might be a need of a certain pause before it launches a new miner. Something like 10-30 seconds would be fine (and would make a nice .conf setting).
I've noticed it before while
playing with
different algo's ^^" Running 10-20 yay's and quickly switching to another algo was a bad idea

I'll add that as a config option, eventually. Until then, my earlier suggestion of having a "sleep" command in a batch file before launching the miner is the best workaround.