After adding voice shortcut to my app when I try to invoke it through custom intent on the device, I get "Sorry, there was a problem with the app" response without any additional info.
In order to debug it, I set the breakpoint in IntentHandler in which constructor of my custom intent is called and confirm method is called but handle method is never called.
The weirdest thing is this is only happening on iPhone 6, on iPhone X with the same iOS (12.1.2) it's working ok. Simulator is also working fine.
In console log I found these messages related:
symptomsd: Entry, display name [siriextension.bundleid]
symptomsd: Continue with bundle name [app.bundleid] , is front 0
symptomsd: [app.bundleid]: Foreground: false
symptomsd: Failed to find process for [app.bundleid]