BIRT JDBC ResultSet Error using Stored Proc with MariaDB

Hi. We're trying to create a BIRT report Data Set in Eclipse, with a result set from a stored proc, using a MariaDB database and Java/JDBC driver. Using the following query syntax:

{call sp_fetch_data(?,?)}

This worked with an earlier MariaDB client version (1.5.9), but with newer versions (I've tried 2.0.3 and 2.7.1), it fails with the following error, and the parameters and output columns are not populated:

A BIRT exception occurred.
Plug-in Provider:Eclipse BIRT Project
Plug-in Name:BIRT Data Engine
Plug-in ID:org.eclipse.birt.data
Version:4.13.0.v202303021806
Error Code:odaconsumer.CannotGetResultSetMetaData
Error Message:Cannot get the result set metadata.
org.eclipse.birt.report.data.oda.jdbc.JDBCException: SQL statement does not return a ResultSet object.
SQL error #1:(conn:64) OUT or INOUT argument 2 for routine mydb.sp_fetch_data is not a variable or NEW pseudo-variable in BEFORE trigger
;
java.sql.SQLSyntaxErrorException: (conn:64) OUT or INOUT argument 2 for routine mydb.sp_fetch_data is not a variable or NEW pseudo-variable in BEFORE trigger

If I switch the MariaDB JDBC driver back to the earlier version (1.5.9), it works again.

I'm using the latest version of Eclipse/BIRT, 4.13.0, and the back end MariaDB is 10.2.17.

Any ideas? Could this be a bug / difference in the newer (v2.x) MariaDB JDBC driver versions, or is there something we need to do differently to work with this version? Thanks.