In order to investigate further we will need the following information:
1. A copy of the load test. This will be a .tstest file on disk.
2. A Fiddler trace of the load test running starting and ending with only one VU. NOTE: If your application uses HTTPS please be sure to check "Decrypte HTTPS traffic" else Fiddler will not capture the load test traffic. In order to force fiddler to capture the load traffic please follow this blogpost.
3. A Fiddler trace of you doing the same thing manually in a browser, not using Test Studio at all.
4. The log from the load agent.
Once I have all this information I should be able to diagnose why it's not working as expected.
Thank you for your cooperation in advance.