Screeners are the brief surveys customers use before a test to help them find the best participants for their research needs. It can be a little confusing when you complete a screener and immediately are sent back to your dashboard. This usually means someone else has just started the test and it is no longer available. Typically, this happens when multiple people are completing the screener at the same time.
Additionally, you may be sent back to your dashboard after clicking "Take Screener". This also happens because another tester has just been started the test.
In either case, after refreshing, the test should be removed from your dashboard. If you encounter any unusual or unexpected behavior related to this, feel free to contact the Support team.