a question about resource exhaust test

hi all,
my components fail the resource exhaust test, but I can’t find the root cause.
In iterations, after unload the last successfully idled instance (for example, the 24th), it fails to load the last failing instance.
this issue happens when I run conformance test application, but not happens when I debug it.
Does any one have met similar problem? Is there any defect in test code?