Why is the orange dot on my iPhone 16 Pro not turning off?

iOS 18 on a 16 Pro - the orange dot was on, indicating the mic is in use. I closed all apps. Checked control center, which said Siri and dictation were using the mic. I barely use Siri and have it only activated with the side button. So I activated Siri and asked why the orange light was on? And why was Siri listening to my conversations? I got a standard response regarding Apple Privacy. 10-20 seconds later the light turns off on its own.

[Re-Titled By Moderator]