one of the viewing button becomes a "@". There is an info message: "Lacking data to view this position. To view whole game, load in last move.".
This means you loaded the game from an earlier position instead of from the latest position. You might have done this accidentally by clicking the View button, which used to be the only way to navigate through the moves of a game. You should follow the instructions and load it from the latest position. Click on the >| button, then click on the View button. This will load the game at the last move, making all past moves accessible without the need to reload any of them.
This means you loaded the game from an earlier position instead of from the latest position. You might have done this accidentally by clicking the View button, which used to be the only way to navigate through the moves of a game. You should follow the instructions and load it from the latest position. Click on the
>|button, then click on the View button. This will load the game at the last move, making all past moves accessible without the need to reload any of them.