Why Doesn't Siri Understand Previously Understood Questions?

Recently I've noticed a problem with Siri, most probably caused by an iOS update. When in my car, using Maps, I was once able to ask it: "Hey Siri, what's my ETA?" And the typical answer would be "You should arrive in XYZ minutes." Now, no matter how many times or in what manner I ask that question, I never get the right [previous] answer.

All of these questions fail.

"Hey Siri, what's my ETA?"

"Hey Siri, what's my estimated time of arrival?"

"Hey Siri, what time/when will I get there?"

"Hey Siri, what time/when I arrive?"

"Hey Siri, when will I get to DESTINATION?"

In every single case, Siri responds: "Here's what I found on the web for TEXT IN BOLD ABOVE. Check it out." !!!! Does Apple really want me to look at my phone and crash my car? I thought that was the whole point of being able to interact with our devices via voice - freedom, safety, convenience, speed...!

What happened to Siri? Does anyone have any ideas?