We just sent out an email blast using MailChimp and a number of people unsubscribed from our list (via MailChimp). How long will it take for their unsubscribe to appear in LGL?
Those updates flow into LGL nightly. They will appear in your integration queue and then you can save them, which will cause the MailChimp status in the constituent record to be updated in LGL.
Even if you don't save the updates from your integration queue, however, there's not much harm. The only impact it has is that it looks like you have a few more subscribers in LGL than you do.