@dannyboy1121 A belated welcome to the Rockstor community.
Note sure about earlier versions producing this error but this can result from ignoring the big red warning against disks on the “Disks” page due to device serial issues. But again this particular error would only be in later versions since we changed to the by-id type disk naming. But if a drive has no serial it can’t be tracked by Rockstor and is thus not supported, hence the warning; we are still a little unrefined in this regard but further improvements are in the works. Please see Device management in Rockstor for a current explanation for this area of Rockstor in more recent versions.
If you present a particular scenario that is not working for you where all the disks in question are without the big red label, ie they have valid and unique serials and then the resulting error we may well be able to address that particular issue, otherwise it’s a little like shooting in the dark and ultimately more frustrating than need be for all parties. Most core functions as you describe are mostly well behaved but only in sane circumstances such as all devices having unique serials. So I would look first to that element of your setup first as it’s is not usual to have quite the level of dysfunction you are apparently experiencing. Especially since it seemed to be working for you in the past. Maybe the rebuild left out some device serial attribution element that was in effect previously.
Maybe a screen shot of the Disks page would help info wise as this is a bit of a puzzler.