Yes, credits do roll over when you downgrade, but with specific conditions:During your current billing cycle, your existing credit balance will remain unchanged on your account.When your next billing cycle begins, two things will happen:1. Your account will switch to the new downgraded plan
2. Your credit balance will be capped at 2x the monthly credit limit of your new planFor example, if your new downgraded plan has a monthly credit limit of 100, your credit balance will be capped at 200 credits when the new billing cycle starts.
Sources:Credit Rollover After Cancelling or Downgrading SubscriptionClay credits overview | Documentation | Clay University