undefined method `cache_key' for nil:NilClass
After enabling the feature flag gitlab_subscription_future_renewal
we saw an increase in 500 errors for some groups gitlab-com/gl-infra/production#4483 (closed)
see sentry error https://sentry.gitlab.net/gitlab/gitlabcom/issues/2607128/?query=correlation_id%3A01F4Y88VKNQFQM09M0SP3WB8WK