How does Ghost calculate MRR for annual signups?

Just started offering an annual membership with a one-month discount and a free 30-day trial.

When people switched over, the MRR went down, which I expected, since almost all took advantage of the free trial. However, as the trials have started ending, the MRR has not gone back up.

Is this a Ghost thing, or a Stripe thing? Should the MRR go back up once the trial ends?