Invoking Siri with side button inconsistent problem

iOS & iPadOS

Greetings, someone else described this bug to me with the first release of iOS 14. I only recently started to see it. I have 14.2.1 on an iPhone 12.

Often but not always when I go to use Siri by holding down the side button it takes quite some time before I get the beep response. I let go of the side button and immediately get the end response beep. I hold the side button again and I get the beep response and and then able to say my query.

Has anybody else seen anything like this? I expected to see it in the known bugs list