What flavor of Aurora were you using, and which RDS engine and version did you switch to?

Within Amazon's Aurora and RDS product families (https://aws.amazon.com/rds/), there are

* Amazon Aurora MySQL

* Amazon Aurora PostgeSQL

* Amazon Aurora Serverless

* Amazon RDS for MySQL

* Amazon RDS for MariaDB

* Amazon RDS for Oracle

* Amazon RDS for SQL Server

plus the variations in different versions (e.g. Amazon RDS for MySQL supports 5.5, 5.6, 5.7, and 8.0).

Without knowing that it's hard to understand how you solved your problem. E.G. If you switced from Aurora MySQL to RDS for MySQL i expect you'd still need to use a tool like pt-osc and copy your tables.