toilet handle prevents flapper from closing sometimes
Turns out I needed to tighten the handle.  It was allowing the handle arm to descend "all the way to the ground" which happens to interfere with the flapper.  But these handles are apparently designed in such a way that they aren't supposed to allow the handle "get too low ever" so if your handle is "pointing straight down" you have a problem.  Mine was fixed by tightening it up again.

Requisite diagram to show arm vs. handle: