Using Siri to "Play (Artist)" responds with "Sure, Here are some popular (Artist) songs" but it never opens the Music app to play them. Even after opening the app and using Siri to play still doesn't work on my iP8+ or iPP9.7. Also, using Siri to play locally saved music is not working either. I have to manually initiate the music through the app to play. I have an Apple Music and iTunes Match subscription. Siri is noticeably slower to respond when searching for music, which is mostly what I even use Siri for in my searches. Reboots haven't resolved the issue. I installed 12.1 via iTunes upgrade from 12.0.1. I've not performed a DFU restore or new installation, yet. I had planned on a DFU installation as new with my devices. Anyone else having this problem?
Update: Well, it works on my MBP with macOS 10.14.1. Using Siri to "Play (Artist)" opens the music app and begins a compilation. Is it just broken for me on iOS or anyone else?
Follow-Up: I was able to resolve the bug by enabling Listen for "Hey Siri". Following the prompts and then restarting the devices. After this, then I used the "Hey Siri" feature and it worked by opening the Music app and playing the audio through the device or my BT speaker. I don't prefer the always-on "Hey Siri" feature. So, I turned off Listen for "Hey Siri", hoping that this would be back to normal with just using the Home button or my BT speaker's microphone. Restarted my devices after disabling it and now the feature works with Siri via the Home button or BT speaker's microphone.