Changed from Hey Siri to different phrase, It Response But Stumbles

bob ~ The heavy denands of voice processing require a consistent supply of power from the battery. And so a weak, aging battery can produce inconsistent results from Siri. So...

Does your iPhone XR still have its original battery?

And what's the Maximum Capacity % here?...

Settings > Battery > Battery Health & Charging

õ¿õ¬

bob ~ 77% is not healthy — being below Apple's suggested level of 80% for having the battery replaced. Correctly processing your voice likely requires peak performance — which may be impacted by your 'significantly degraded' battery.

...So have the weak, aging battery replaced and see if that cures Siri's 'stumbles':

iPhone Battery Service

About genuine iPhone batteries

Repair Provider Verification

(Articles found by searching Apple's Knowledge Base.)

õ¿õ¬

bob ~ How many words in the phrase?

...Just as a test, change the phrase to a shorter one — does Siri then do better?

õ¿õ¬

Ok.

Now you know Siri is not broken,

But you have discovered that under certain conditions, changing "Hey Siri" to something else gives you trouble.

How bad do you want this to work?

If this is important to you, contact apple support and work with them to a resolution or filing a formal, tracked bug report. You may need to work with a specialist to complete the investigation. Don't let them tell you it's fine to get rid of you unless it really IS fine.

Support

If this is not worth that much effort, consider posting a terse description of the problem as a bug report on the Product Feedback pages.

Product Feedback - Apple

I expect you get the "I don't understand" because when Siri gets set ready to parse your request, it can see you said something other than hey Siri, but there is nothing to do.

try saying, without pausing, "hey Siri text Fred I am leaving now"

bob ~ Staying on a charger won't help if that original, old battery is weak or severely depleted. So...

On that Settings > Battery pane, please scroll down to Battery Health & Charging and tap it. Then, in the resulting pane, tell us what the Maximum Capacity % is.

õ¿õ¬