I received the email and code in my Halo Insider account and when I redeemed it on steam, it marks it as a duplicate. Does anyone know if this process is normal or is it the same key as the last flight? I remember that at the end of the last technical test, a legend appeared on steam that the editor removed it from the library, so the editor will also put it back? I am new to this type of test, could someone give me comfort 
I don’t want to be left out of this new technical test: (((
The download isn’t available until tomorrow night, and I’ve seen people state that the current Steam key is for the last MCC Season 8 flight, which is not currently open.
Closing per the above ^
The code you’re looking at is either for the MCC Season 8 flight or the previous Halo Infinite tech preview, both of which have ended and are no longer accessible. if you have your pre-selection email already, it’s just a case of waiting for the actual invites to be sent out tomorrow evening (PST).
Depending on your email provider the pre-selection emails can be quite delayed and/or turn up in strange folders. If you Use gmail or outlook, check your other folders [focused/non-focused]/inbox/junk to see if it’s hiding somewhere.