Sorry I'm not understanding 100% but I do believe the gold status was granted prior to DC, just like Vistana was automatic lifetime gold with Westin back in the day, for anyone who owned (but maybe only direct purchases?). When they merged the two programs you got whichever status was higher in either of your accounts, so if you were Silver in both you would be Silver in Bonvoy, but if you were lifetime gold in one you were lifetime gold in Bonvoy. That was my understanding. I got a boost after DC to platinum.
OTOH, I recently used owner services to help answer some questions about an upcoming reservation and they already had my marriott bonvoy account info and linked it to the reservations I never gave this to Vistana, so I assumed that the two systems must have already been linked. I'm assuming that I will get elite night credits for these reservations. So if you have had many nights at Vistana perhaps they are giving you credit for those stays. But seems that should be reflected in your nights count as well, so who knows why the change in status. I don't think it has anything to do with the points value of your mandatory weeks though because I would also have a bump in status from adding the points value of my mandatory week and I don't see that reflected in my Bonvoy account. At least not yet...