Hi Patrick - You are right, rescue inhalers don't usually have this caution because they are meant to be carried along.

I only see the caution on my Symbicort/Breyna inhaler, which contains a combination of drugs. When I used a different, 3 drug combo, it also had the warning. My grandson uses an inhaler that will sometimes misfire if it is not shaken for at least 15 seconds.

That said, I have only ever experience a "misfire" of albuterol or levalbuterol if the inhaler is nearly empty, or if it is very near the expiration date. My local pharmacist says it can also happen if the inhalers have been frozen or stored in too hot a temperature (like in the car in summer.) If that didn't happen in your possession, they said it should be returned to them for replacement.

Have you had albuterol inhalers misfire?