When you select auto enhance it will reduce noise when using a high ISO setting and automatically adjust photo brightness.
Have never used auto enhance. I usually leave my settings on auto or for indoor shots or unusual lighting situations like high/low contrast I use HDR (high dynamic range)
Looked for "flickering rectangle on top of mode" but it wasn't there. Only thing that flickers (on/off) is the rectangle in the middle of the screen (indicates what the lens will focus on)
hope this helps !