Hi @HughesTooling,
That was my first thought. At some point, I disabled the Design History... but I put it back and my user parameters are still nowhere to be seen. To add to what you said, I understand that, once the design history is disabled, the option "Change Parameters" isn't accessible at all, for any parameters.
FYI. I disable the Design History in order to be able to shuffle around Components/Body that I wanted to rearrange within other Components. Somehow, I couldn't shuffle thing around (drag and drop) without History disabled. I always enable the history right after and never done actual design without.
I feel like all this is somewhat the cause of the issue, but not sure how. Just because the "correct" version I had less "messing around" with the components. Even though, all in all, I can't understand how simple variables could be wiped out from memory and literally disappear!? Granted my "newbie" design practice is horrific and I'll have to be more thoughtful and avoid to disable the Design History as a work around.