TCPIP vs external interrupt
Why running TCPIP inserts random delays into the external interrupt response time. External interrupt has priority 7 and uses SRS. Nothing else with priority 7.  The TCPIP server is a Harmony example.
If the server is not running, the external interrupt delay is constant  (1us).
After starting the server, it changes between 1 - 2 us.
I do not know what to try anymore.

I'm currently stuck on the "Learn Standard Open Redirect Preventions" challenge of the "App Logic Vulnerability Prevention" module.

The challenge is to submit a valid open redirect attack starting from the Standard Redirect Protections Challenge tab.

However, the links on this page are all to standard record pages, where the hack (e.g changing retURL to returl) won't work (it only works on VF pages).

Even if I attempt this and check the challenge, the error I get states: "It doesn't appear that you've successfully redirected to an external website using the Visualforce page. Please try again." - so it implies that it expects me executing this from a custom VF page.

Can anyone give me some advice on where I'm missing something on the challenge?