Escrow is typically closed when:

Signing the purchase agreement merely initiates the escrow process but doesn't complete it. Many conditions must still be fulfilled before escrow can close.

Loan approval is typically just one condition that must be met during escrow. The loan being approved doesn't guarantee all other conditions have been satisfied or that documents have been recorded.

Paying the deposit is an early step in the escrow process that demonstrates good faith but doesn't signify completion. Many additional steps must occur before escrow can close.