I was using my LZW36 Fan+Light combo switch as the test for my C-7 which is currently in blue light stasis. With the update, there are now embedded drivers for the LZW36, but I've been using Inovelli's drivers since they give way more customization and control from the device page. I went through the process of adding it back into my C-5 which is up-to-date and HE automatically assigns the system driver to the device during inclusion. When I change from the system to the user driver, I end up with 4 child devices as shown here. The top two were created by the system driver and the bottom two created after changing the driver type of the parent.
HE chooses what it thinks the best driver is at inclusion based on the device fingerprint. If both user and built-in driver matches, I'm pretty sure it favors the user driver, but your experience above suggests the exact opposite, so now I'm not really sure.
Last I tried, Hubitat's built-in driver created the "Fan" and "Light" child devices as un-deletable component devices. This is fine if you stick with their driver but annoying if you don't. If that is still the case, there is no way to delete them until they change that, and even then, you'll have to delete the "parent" (main LZW36) device. Ignoring them works just as well (they won't function unless the parent driver knows how to interpret what the send). Anyway, I assume creating them as this type was an accident on Hubitat's part, and I know Inovelli mentioned at least once. So hopefully that will change in a future hub firmware version.
