I've been using WAPT Pro 2.5 for a while now, and I recently started running tests with more total users than I had before. I generally run using "ramp-up load".
This is the second time I've seen this; the first was an 8-hour 1035-user (across both profiles) run where the last 35 users exhibited the problem, this one was 1035 users over 24 hours with about the last 100 users exhibiting the problem. I never saw this problem on previous runs, but those didn't get over 700 users.
Is this a known problem? Is this a factor of having too few load agents? Is this something that would be fixed in a more recent version of WAPT?