I use the Overcast app for listening to podcasts. Sometimes when I say "play Overcast" it will play, other times it will not. When it doesn't play, it will either say it doesn't understand, or it will say I need to unlock my iPhone. Or it will start a free trial of Apple Music and start playing songs by some band called Overcast. This is crazy. The app is extremely popular, and the command is very simple. I have also tried using different syntax ("tell the app Overcast to play", "play the Overcast app"), and have not been able to find anything that reliably works.

It is similarly unreliable with navigation and calling restaurants. If I tell it to call Restaurant X in Palo Alto, it will tell me that it couldn't find that in my Contacts. No shit — I'm not asking about my Contacts. I have to literally tell it to search for the restaurant in Palo Alto, then listen to it tell me about the restaurant (how many stars, how far in which direction, that it can navigate or call), then tell it to call. There's no reason it shouldn't be a simple "call X in town Y". IME this used to work, but has been increasingly broken.