I recorded a 2 hour team live event earlier today. However when I go to download a recording of the file I seem to be having an issue. The download of the recording starts and I can see it in my downloads folder, yet when I checked back 20mins later the file had disappeared from the folder (and this occurred with repeated attempts). I have been able to download a short video we recorded as a practice a couple of days ago which was only 2mins and 4.5MB. That worked absolutely fine.
Do you have the same problem if you try to download the alternative recording, there are always two recordings. Also check from another computer (or internet connection) and from Teams client, if you open the Live event meeting in the calendar you will be able to download the recordings from there.