Reply from customer not included in request

Reply from customer not included in request

This does not happen with all requests and I have not been able to see a pattern, but multiple replies from customers will not be included in a request that they were sent from. Meaning, when I am in request ##350## and send an email to a person, their reply back to the system is not included in ticket ##350##, but creates a new ticket, that I must them manually merge with the original ##350##.

I would like to know how to correct this as it is super annoying and a lot of extra work.