Aurora RDS PostgreSQL Graceful Shutdown - Still receives incoming requests while it's getting removed?

Hi there.

I noticed that my Aurora PSQL reader DBs are still getting calls even tho they are getting removed.

AFAIK The RDS DB should cut off the reader dbs if they are in a removal state, and should only deal with the existing queries within 3 minutes of the graceful shutdown period (https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/USER_DeleteCluster.html), but apparently that's not the case for me.

Our app got a pre_ping option to run an empty query on the DB to ensure it's still active and run the query afterward. It always ensures that the DB is active and ready with it. But I saw a few cases that passed the pre_ping but failed to run the actual DB query, which means the DB was accepting the call till the moment that it was fully terminated. If the reader DB fully closes its connection during the termination flow, then this should not happen.

Can someone give me some advice? Where should I start to look into this?

Any kind of help would be appreciated.

Thanks!

• My Aurora is at PSQL v14.7