My solved tickets are being counted as unreplied tickets. According to tickets metrics, unreplied tickets are the number of tickets that have not received an agent response as far as I know.
However, I have replied these tickets of course, and submit as a solved. I have attached an image below regarding to ticket data and chat history as a reference.
If you see ticket #5859 above chat image(right), definitely you could check 'agent reply' and 'solved status'. However, on the ticket date table(top image), #5859 is counted as an 'unreplied ticket' too.