No
Is it that weird
No. Quite frankly, quite a few Chess players play decent openings/defences up to 15 moves or so and then their middlegame spirals downhill. This is why it is very important to play over complete games in the opening systems/defences you like (and the variations steming from them that you are likely to face) to see how the games "flow" and to see the likely endgames that may ensue from them.
Is it that weird that me, a 400 rated player knows the Ruy Lopez well.