Using Siri to reply to group text messages

iOS & iPadOS

Has anyone had success using Siri on the locked screen to reply to group text messages?

Ever since updating to iOS 12, when I get a message on the locked screen and ask Siri to "reply to text", Siri asks "To whom do you want to reply?" and expects me to enumerate each person to whom the original group message was sent. I have tried saying things like "reply to group", "reply to everyone", "reply all", etc., but Siri still wants me to enumerate each recipient.

Prior to iOS 12 I was able to simply say "reply to text" and my reply would be sent to everyone on the list.

I've written to Apple Accessibility about this and they asked me to run some diagnostics but never gave any good advice.

Any ideas?

I am now running an iPhone XR with iOS 12.1.3.