"Just curious, would this design be prone to possible AD/ND's?"
No more so than any other semi-auto at the time.
Here's some interesting pix of the sight safety in operation:
I had thought that it only would engage when the hammer was fully cocked, much like the 1911, but that's obviously not the case.
It also appears that its main function was to shield the firing pin and block the hammer.
I've never actually handled a 1900 with a sight safety to the point where I've been able to examine it closely and see how it functions (they're pretty rare, with only about 3,000 made), so I can't tell you how sure of a safety mechanism it was.