Did it keep the attribute on the sheet, and just empty the data, or did the attribute containing this data get removed? If the attribute(s) is still on the sheet, but missing info, then it has been wiped. If the attribute(s) aren't there any more, then theyve just been hidden and the data is still there. In the second place raising an issue on github and contacting roll20 directly (<a href="mailto:team@roll20.net" rel="nofollow">team@roll20.net</a>) might get them to roll back the sheet. That will fix it. If the first case, you need to do that and get roll20 to rollbac your campaign to before the new sheet went live. Emailing roll20 is the best bet here, explaining the situation.