DeviceOS 5.6.0 using System.on(button_final_click) and "2-click" operation?

I have some code migrating from Gen2 and Gen3 devices now running on Photon2 devices using OS 5.6.0. I use Mode button single and double clicks to boot up the device into different operational modes.

System.on(button_final_click, buttonClickHandler);

It works for single and triple clicks of the Mode button, but fails for double clicks. When double clicked the Photon2 resets and extinguishes the LED and sits is in an inoperable state.

Feature or Bug? (A bug in my case...)
Any assistance or documentation cite appreciated.

I found this post that explains what's happening:

The operative verbiage is "I'm not sure why it does that"...
My bug assertion still stands.