I have a few pipes that have behaved like this and have seemingly sucked the life out of anything I have put in them. I have absolutely no idea what the cause was or is but I do know that it happens and I found they have come around eventually but for quite some time there was a frustratingly muted and insipid smoking experience. It's happened with new pipes, well-smoked estate pipes and I have had it happen after a thorough cleaning which including taking the cake right back.
My bet is that is you keep smoking it then eventually the flavour will show up. It may take a while though.
My bet is that is you keep smoking it then eventually the flavour will show up. It may take a while though.