The tutorial was deleting your save
The loop was not a cosmetic stall. An empty party made the client wipe its own save and close, then do it again on the next launch. That is fixed, progress is remembered, and the title-screen button now signs you in with a Groot ID.
Take the client from the download page again. This build is r0021 and the server refuses the one published last night, so yesterday's install will be turned away.
The notice before this one named the wrong culprit. It said the avatar cinematic looped because the server answered the new summoner under tags the client could not parse. That was true and it was fixed, but it was not what was happening to people. The real fault was worse: the client treats a zero-length active party as unrecoverable, and its idea of recovering is to delete the local save and close itself. So the sequence was reaching Home with no party, the save wiped, the app shut. The next launch then had no user, ran avatar creation again, arrived at the same empty party, and wiped again. Anyone caught in that was not watching a cinematic repeat. They were being reset each time.
The active party has exactly one source, and this server was capable of sending it empty. The fallback that should have filled it was guarded on a unit id that reads zero whenever seeding the starting unit had failed, and that failure was only written to a log where nobody was looking. The server now re-seeds, falls back to any unit the account owns, and if it somehow still has nothing it refuses with an error rather than sending an empty party. An error only closes the client. An empty party deletes the save first, and that difference is the entire bug.
Tutorial and cinematic progress is remembered now as well. The three commands that report what you have cleared and what you have watched all used to answer with nothing, so every time you came back Home the client was told you had done none of it and played the opening again.
The title-screen sign-in button works. Signing in with a Groot ID from inside the game had three separate faults and all three are fixed. The portal was stamping its rate-limit clock even on the polls it refused, so a client that asked too eagerly was told to slow down forever and never served. The client gave up after 240 seconds on a code that lives for 600. And once you had signed in the button hid itself for good, because it only shows when you are signed out and the check counted you as signed in without a usable ticket. Tap it, type the short code it shows you at groot.games, approve it, and the game is signed in to your passport.
That changes what an account is. Leave the button alone and the account still belongs to the device, exactly as before. Sign in and the account becomes your passport's, which is what lets it follow you to another handset.
The Facebook branding is gone from the title screen. The client streams that art from this server rather than reading it out of the package, which is why patching the package alone changed nothing anyone could see.
Nothing here carries over. The world is cleared before it opens properly.
If the tutorial still traps you, or the sign-in button does not come back when you expect it, say so with the device model and the Android version. Most of this release is what a real device found, and the rest will be found the same way.