This is the key.
Your sticker will specify whether the tank has been O2 cleaned and is safe for partial pressure blending up to 100% O2, or whether it is suitable ONLY for banked blends up to 40%.
If you refill an O2 clean tank with banked Nitrox, you're likely fine (but ask the shop if their gas is hyperfiltered or O2 clean).
If you refill any tank (O2 clean or not) with "plain old air", it loses its status and should not be used for partial pressure blending (OR banked Nitrox) until recleaned.
Just curious... why can't a tank that is not O2 cleaned be filled with banked nitrox? I ask only because you state that here, but I've witnessed plenty of non-O2 clean tanks filled from a 32 bank with zero problems or concerns.