For example: You create the account, and passphrase A is shown on screen. You enter it in the client the first time, but you unfortunately make a small typo, so you end up in account B. Every combination of chars opens a new (empty) account. You think passphrase A matches account B, so you send your tokens to account B. Now when you enter your passphrase for A without the typo, it doesn't work for account B. When you login with passphrase A, you end up in the real account A, which has 0 ARDR in it. You could try to find out what password B (with the typo) is, that gets you to account B with the ARDR in it, but you'll have to be lucky to find the typo.