As ntozier already said, the replies are taken as an internal note and this makes totally sense to avoid different confusing responses from several agents to one user, so for example:User Alice opens a ticket... she e.g. asks for an installation of a software.Agents Bob and Charlie receive an email that Alice opened a new ticket and wants the installation of a software. Bob responds and says "NO, installation not possible" and at the same time Charlie responds and says "YES, installation is possible". So now Alice would be totally confused.To avoid such situations osTicket notes email replies from agents as internal notes instead of sending them to the end user. The above situation could not happen in osTicket since there is the "agent collision avoidance" feature which locks a ticket for the defined time (Admin Panel > Settings > Tickets > Agent collision avoidance) so that double / confusing responses shouldn't be possible.Hope that explains the sense why osTicket acts like that ;)