That is a strange one. I suggest starting a new post with your findings as this wiki thread was intended just for development notes. So folks may be more willing to respond to a general thread than this one. And as indicated here the bcache support is fledgling currently as it depends on so many custom arrangements such as the custom udev rule etc detailed above.
Also note that development on our CentOS variant ceased as of 3.9.2-57. So any updates that we may need to address issues with regard to bchache will only appear in our Rockstor 4 variant which is now ‘Built on openSUSE’ see:
I’ve not personnaly tried our bcache support in the ‘Build on openSUSE’ effort either so that would be particularly helpful for the Rockstor 4 endeavour. You may also find that it is not longer a requirement to install it as it may be part of the base Leap 15.2 that we are basing our pending installer on see: