Aurora MySQL database got stuck in Upgrading status

Hello,

I tried to upgrade MySQL to the latest minor version available but it got stuck in Upgrading status. It's been more than 3 hours and still not finished. I already restored a snapshot to a new cluster/instance for my team to proceed but I still need to get the original cluster/instance working. What else can I do?

Event logs:
November 17th 2020, 2:03:48 pm UTC The crash loop due to OOM
November 17th 2020, 1:46:18 pm UTC Error restarting mysql: Engine bootstrap failed with no mysqld process running...
November 17th 2020, 1:45:56 pm UTC Error restarting mysql: Engine bootstrap failed with no mysqld process running...
November 17th 2020, 1:23:41 pm UTC DB instance restarted
November 17th 2020, 1:16:25 pm UTC DB instance restarted
November 17th 2020, 1:16:12 pm UTC Error restarting mysql: Engine bootstrap failed with no mysqld process running...
November 17th 2020, 1:00:26 pm UTC DB instance restarted
November 17th 2020, 12:51:17 pm UTC The database process was killed by the OS due to excessive memory consumption. It is recommended to tune your database workload and/or parameter usage to reduce memory consumption.
November 17th 2020, 12:49:12 pm UTC Error restarting mysql: Engine bootstrap failed with no mysqld process running...
November 17th 2020, 12:48:10 pm UTC Error restarting mysql: Engine bootstrap failed with no mysqld process running...
November 17th 2020, 12:47:01 pm UTC Error restarting mysql: Could not verify and start mysqld.
November 17th 2020, 12:38:40 pm UTC Error restarting mysql: Engine bootstrap failed with no mysqld process running...

Thanks
Lino