If mIRC is using GetWindowRect this is a bug,
If mIRC is using GetClientRect it's not. In that case it would be a Windows behaviour.
Technicality aside, I can see the use of either value though.. some people might need the menusize incorporated into the height, others may not, though I suppose if mIRC reported the "proper" client height you could do (windowheight - clientheight) to get the menu bar size.
