Spring boot Postgres not return null when empty - sql

Question

I am using spring boot and spring data JPA with a Postgres database. There is a weird behaviour that happens when query something and the result is nothing.
In a lot of databases and projects when I make a query and the result was empty the returned object to java was null.
For example:
#Query(value = "select * from notification where WEBCODE = :webCode OR USERNAME = :username", nativeQuery = true)
Page<NotificationSQL> getNotificationsAsPage(#Param( "webCode" ) String webCode,#Param( "username" ) String username, Pageable pageable);
In this case I was suppose to get a null page. but in this case I am receiving an exception
org.springframework.dao.InvalidDataAccessResourceUsageException: could not extract ResultSet; SQL [n/a]; nested exception is org.hibernate.exception.SQLGrammarException: could not extract ResultSet
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.convertHibernateAccessException(HibernateJpaDialect.java:259)
...
Caused by: org.postgresql.util.PSQLException: ERROR: operator does not exist: character varying = bytea
Hint: No operator matches the given name and argument types. You might need to add explicit type casts.
Position: 42
at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2552)
I do not understand why it does not just return a null object. It happens the same with the rest of the queries when empty rows and different objects as List classes. In a lot of projects this has not happen to me, the returned object when the query was right and empty rows was a null.
If the parameters are not null it works perfect, but the point is that these parameters sometimes are null and , as it can be seen in the image, the query works nice but with a result of empty rows.
Thanks in advance