RDS MariaDB Blue/Green deployment fails to create due to storage configuration upgrade task failure

I have an RDS MariaDB setup with 2 replicas. I have sucessfully used Blue/Green deployments with this setup before. Now though, when I try to create a new Blue/Green deployment the process fails after only one green instance is created with "Creation of blue/green deployment failed due to storage configuration upgrade task failure. Retry the upgrade."

This has occured three times in a row now. I've tried various combinations of MariaDB engine versions and parameter groups when creating the deployment, but this hasn't made any difference. There doesn't appear to be anything else I can alter at the initial creation stage.

Primary instance is MariaDB 10.6.8 in multi-az mode with IO1 storage. The 2 replicas are MariaDB 10.6.14 in single AZ mode with GP3 storage.

How can I resolve this so that I am able to create a working Blue/Green deployment?