If you want to move between different security “levels” in Hubitat (or any Z-Wave controller), you’ll have to re-pair. The next hub firmware version, 2.2.3, will introduce some changes that make it easy for developers to work with devices that are paired with S0 or any S2 level, and a quick look at Inovelli’s driver suggests that it would be pretty easy for them to adapt to this (just a modification of their
commands(Command cmd) method that they already wrote for a similar purpose), though it’s possible there is more to their code than I understand. It’s possible for a driver author to do this somewhat manually even with the current hub firmware, but I’d wait until the platform methods are available in the next release personally.
In the meantime, Hubitat has built-in drivers for most Inovelli devices now, and those drivers work fine with S2. Alternatively, with Inovelli’s drivers, the devices could be included without S2 or S0 by unchecking all options during pairing (actually, S0 probably would work, but there are lots of reasons I wouldn’t use it here). If a device isn’t including properly (as opposed to just not fully functioning afterwards), e.g., it gets stuck on “initializing,” then that is unrelated to the driver, and the steps Hubitat staff outlined (as Bryan did above but you can also read on the Hubitat forums) to help may work around it until they are able to identify a fix.
In my testing, the current-gen Inovellis always asked for a key when pairing. If yours eventually stopped, I’m not sure why, but it seems unlikely to be related to the device since they should always request S2 if they support it (and there is no separate pairing procedure, like pressing the buttons differently, for S2 vs. no security like I’ve seen on most S0 devices).