When Zoeys mom has just spoken to Deb and receives a text message from Zoey, the conversation that is shown isn't possible. In it you can see that Zoey sent two messages, luring her mom into going to the bar/café to meet Deb, but the last message that has been sent is blue. Which would mean that Zoeys mom has sent the message to herself asking: "How's it going?". In the next scene when Zoeys phone is shown, the same conversation is shown, but it shows that the message Zoeys mom sends her does in fact get 'gray' when it is sent to someone else. Similar to how 'Facebook Messenger' displays conversations on phones.