The "divide-and-conquer" paradigm extends to selection of input data as well: A few minutes testing known input sets, starting with the simplest, can save hours

The "divide-and-conquer" paradigm extends to selection of input data as well: A few minutes testing known input sets, starting with the simplest, can save hours with the debugger. If none of the simpler input sets at hand repros the failure, it may be profitable to attempt to craft one. Now with a minimal failure case in hand, proceed with temporal "divide-and-conquer" along the lines you've so nicely laid out.