When I apply a fetch graph to a query, it is correctly applied to the first result: eager associations that are not mentioned in the fetch graph are overridden and made lazy.
However, this is not true for query results beyond the first one (index 1, 2, etc.): for those results, eager associations are loaded eagerly, even if they are not mentioned in the fetch graph.
This used to work in 5.4.18.Final.
PR coming, with a test case and hopefully a fix.