Amazon Managed Grafana ENIs cannot be deleted

Hello,

I have created an Amazon Managed Grafana instance and attached a Security Group to it. I am using CDK to manage the infrastructure. I then used CDK to delete the infrastructure, which included a VPC created for this purpose. Upon attempting to delete the VPC, I get an error around not being able to delete the security groups due to the ENIs being in use. I check the corresponding ENIs and they are for the Grafana instance that I had deleted.

When I attempt to detach the ENI, it says the ENI is still in use (it isn't?). And then when I click the "Force Detach" button, I still do not have the option to delete it. This is preventing me from deleting the security group and thus the VPC. Does anyone have any ideas into what could cause this? The ENI's description indicates it is for Grafana and that it is using Fargate on the backend (although this is hidden).