Spring looking for PostgreSql driver, but I'm using JTDS - spring-boot

Question

Loading a spring cloud dataflow app fails with this log:
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Hikari.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception; nested exception is java.lang.IllegalStateException: Cannot load driver class: org.postgresql.Driver
But configuration is:
spring.jpa.database=sybase
spring.datasource.url=jdbc:jtds:sybase://xxx:X000/xxxx;autoCommit=false;appName=dataflow
spring.datasource.username=xx
spring.datasource.password=xxx
spring.datasource.driver-class-name=net.sourceforge.jtds.jdbc.Driver
spring.datasource.hikari.driver-class-name=net.sourceforge.jtdatasource.jdbc.Driver
spring.datasource.hikari.pool-name=datasource-pool
spring.datasource.hikari.connection-timeout=3000
spring.datasource.hikari.maximum-pool-size=2
spring.datasource.hikari.minimum-idle=0
spring.datasource.hikari.connection-test-query=SELECT 1
spring.datasource.hikari.auto-commit=false
spring.datasource.hikari.transaction-isolation=TRANSACTION_READ_COMMITTED
Dependency:
<dependency>
<groupId>net.sourceforge.jtds</groupId>
<artifactId>jtds</artifactId>
<version>1.3.1</version>
</dependency>
PostgreSql is never specified.
Using spring boot 2.3.3
Update:
I think something in spring dataflow context is setting the driver, because it works if I create my own configuration class and don't use spring.datasource prefix:
#Configuration
public class DataSourceConfiguration {
#Bean
#Primary
#ConfigurationProperties("spring.ds")
public DataSourceProperties dataSourceProperties() {
return new DataSourceProperties();
}
#Bean
#Primary
#ConfigurationProperties("spring.ds.hikari")
public HikariDataSource sybaseDataSource() {
return dataSourceProperties().initializeDataSourceBuilder().type(HikariDataSource.class).build();
}
}