Welcome! This forum has a treasure trove of great info – Scouters helping Scouters! Just a heads up, though - all content, information, and opinions shared on this forum are those of the author, not the BSA.
I just had a volunteer reach out because a scout who has been in scoutbook for the past 4 years, and is still current on the charter, disappeared from Scoutbook when they went into the system to update an advancement. Advice that I can give the volunteer?
Just as a side comment, in case it’s relevant, we’ve seen this occur a couple of times when a unit admin has ended a current patrol membership instead of transferring the scout to the new patrol. If that’s the scout’s only unit membership in Scoutbook (which if you sort the scouts into patrols is generally true), then the scout will disappear (at least that has been our experience).