Problem inserting in Aurora Serverless (via Data API) with foreign key

I'm using Aurora Serverless with Data API (AWS.RDSDataService class for node.js).
When I'm trying to insert two related (one-to-many) records in a single transaction I'm getting "Cannot add or update a child row: a foreign key constraint fails".
I'm sure I'm doing it in a single transaction and parent record is inserted first. But it looks like it's not there when I insert child record.