Elastic Beanstalk deployment failing because of a dangling security group

When doing a deployment with Elastic Beanstalk, we got the following error:

ERROR: Configuration validation exception: Invalid option value: 'sg-fdd33e89' (Namespace: 'aws:autoscaling:launchconfiguration', OptionName: 'SecurityGroups'): The security group having id 'sg-fdd33e89' does not exist.

Things probably related:

• We have custom security group settings for the ELB in .ebextensions
• We had earlier cloned this particular EB environment from an older EB environment and had problems with being unable to temrinate the old environment because of this security group.

(Already solved this but sharing the question in case it helps somebody else)