DMS task maximum number of schemas or tables

I am attempting to migrate a set of databases from Mysql (self-hosted) to Redshift. We segment customer data by using a single database per tenant. So for this migration I have a couple thousand databases, each with ~200 tables.

When setting up a migration task in DMS (using a dms.t3.large instance size), and using a selection rule like where schema name is like '%' and Source table name is like '%', include, I then encounter an error that No tables were found at task initialization....

If I setup my selection as where schema name is like 'a%' and Source table name is like '%', include (ie, only get databases / schemas that start with 'a'), then it will work and do the migration. So my assumption is that I have hit some kind of maximum number of schemas when I try to setup a single DMS task to migrate all tables.

Is this correct? Is there a maximum number of schemas or tables that a single DMS task can handle? If so, what is that value so I can try and figure out how to break up my existing databases within that limit.

Thanks!