Front Facing "Flash" - But Just a Circle

Hi all, just had this happen once (and it took a nice photo so I'm glad), but my settings are flash off...

Took a wide angle selfie, and it lit up a white/amber circle on the screen, and that actually provided just enough light without washing out the foreground.

Can't seem to replicate it. Can't find any other references online except this post: https://www.reddit.com/r/oneui/comments/127ae79/part_of_samsungs_implementation_of_night_mode_on/

Any ideas when it triggers? Would actually like to use it instead of the default front facing flash.