Sorry, It took me a while to test. I take everything offline during monsoon season due to lightning.
Anyhow, I am happy to report RBI is working fine.
The RBI flash/flush produces a very characteristic fixed noise pattern in the Dark frames.
I was able to turn the RBI on flash/flush mode on and off a couple times
I won't be able to test it on the sky for a couple months until I resume imaging in the fall.
However, I have no doubt the feature has is now available for operation.
You might consider a wider test with next beta release.