In EAP 7.1, the customer was initially facing the DB2 driver exception:

DB2 SQL Error: SQLCODE=-840, SQLSTATE=54004, SQLERRMC=null, DRIVER=4.19.66

From DB2: Explanation: Number of selected items exceeds 8000

To resolve this, the customer changed their ToOne associations to @LazyToOne(LazyToOneOption.PROXY)

This resolved the issue in EAP 7.1

After migrating to EAP 7.4, the issue is occurring again, and the customer thinks that lazy loading is not working.

We collected sql trace logs from both environments to compare the queries. Both queries are quite large, but the query from EAP 7.4 does appear to be larger.

I have attached both logs and a docx that the customer provided, which contains the relevant entities, etc.