Emails with different subjects from same client

Hello! I”m using the chrome extension for gmail and have a client who keeps starting new email threads with new subject lines each time they email me. Because of this I’m finding that their emails are not propagating into my workspace for the client, and it’s causing a lot of confusion, overwhelm and frustration on my end. I use this extension so I don’t have to keep logging into my gmail account. Is there a way to remedy this? Am I missing something? Honestly if this is a feature that doesn’t work for this extension, it’s fairly useless.