Do they currently calculate lifetime status correctly?
Right after I combined my SPG and Marriott accounts I had the following status on https://www.marriott.com/rewards/myAccount/lifeTimeNightDetails.mi:
Years as Silver, Gold or Platinum: 0
Years as Gold or Platinum: 0
Years as Platinum: 0
Apparently these were just default placeholder numbers.
A few days later I see the following numbers:
Years as Silver, Gold or Platinum: 12
Years as Gold or Platinum: 12
Years as Platinum: 12
Apparently these also are not true because I have less than 12 years of Platinum status.
As for my recollection I have 7 or less years of either Gold or Platinum status.
And what do you see on https://www.marriott.com/rewards/myAccount/lifeTimeNightDetails.mi?
Do these numbers make sense for you?