Thanks for reaching out about this here in the Community and welcome!
Unfortunately, as @ListenToGlobal mentions it's not possible to view the history of playlists once they've been updated.
If you like any of the tracks in your Release Radar playlist, be sure to save them or add them to another playlist before it updates.
On another note, it seems like being able to see the history of playlists that have been updated is something other Spotify users would like to see as well. We'd suggest heading over to this Idea and adding your +VOTE there. You can also consider adding your feedback in a comment there as well to contribute to the discussion.
You can also take a lookhere to find out more information about how the Ideas Exchange works and how your feedback reaches Spotify.
Hope this helps clarify things, but don't hesitate to give us a shout if there's anything else we can help with!
Have a lovely day :)
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