If you start typing with /tell you cannot always press tab to complete the players name. (you have to enter the players name first then go back and type /tell) Also, sometimes a '/tell' is in a white font and you cannot '/r' to reply, and the messages are sent as "whispers". Could this be fixed? Is there a conflict between two plugins here?
Try using /msg instead. As far as I can tell, it always works as intended. The /tell alias is conflicting with something else, possibly the vanilla command.
To be completely honest, I have no idea. It isn't a straightforward conflict where one plugin has overridden another one. It seems to randomly switch between the herochat functionality and whatever is causing the other, vanilla-like functionality.