Enable VoiceOver and select the Alex US English voice.
Invoke Siri by pressing and holding the side button or home button, or with the Hey Siri command.
You will hear the Siri chime, but before you can speak your command, VoiceOver will say "Possible text, followed by the time".
This does not happen 100% of the time, but most of the time.
Only observed when using the Alex VoiceOver voice, but of course it is possible that there are other affected voices.