A frustrating bug in the game, most likely due to poor multi-platform development or inadequate testing.
Quite frequently, after selecting "Career" mode, the game would not allow me to resume from where I last left off. Other symptoms include missing artefacts and scanned ghosts.
To fix this, simply quit the game and start it up again. It seems that you have to make sure that your Playstation profile has finished signing in before starting the game.
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