Possible Photoshop Beta Bug with Magic Wand and Generative Fill

I was trying to create a surrounding black border with starry glitter using the magic wand. Started with a 1920x1080 black background - increased canvas to 2000x160 px (so I could have an 80px border).

• Then selected the transparent border area with the magic wand 
• clicked on "generative fill"
• typed in the prompt "microscopic white glitter star particles scattered on black background, 4k, high detail"
• clicked on "generate" - all in first image.

It began the generative process (with Firefly Image3), and it progressed for 2 seconds and quit and went back to a blank "generative fill" - as if I never typed anything in! Now keeps doing that every time. - 2nd image