Hammock task resource leveling fails

Why would hammock task resource leveling fail even though there are not resource conflicts?

Tasks for Release 1 and Release 2 are completed with allocated resources before hammock task “Enhancements for Release 3” starts.

It does not matter whether I allocate the same resource or other resources to the hammock task. There is still always the error message:

“This task couldn’t be fully resource leveled and therefore the resources it is assigned to may remain overloaded. The task hasn’t been moved. Resource leveling failed because there wasn’t enough time to perform the task while honoring these constraints:
This hammock task has assigned resources that are also assigned to tasks in the dependency chain that determines the hammock’s end date. This could cause the hammock to stretch endlessly.”

Is this a bug or what I’m doing wrong?

See attached screenshot: