Looking at the 2.7.11 code, I think it should fail properly at this line <https://hg.python.org/cpython/file/v2.7.11/Modules/stropmodule.c#l1113>, which checks if the change in size of all the replacements overflows. Is there a way to get a stack trace or similar on Windows?

Your video only shows the operation taking a long time or hanging as far as I can tell, not the Python program crashing. I would expect the call to raise MemoryError fairly quickly, after it has counted all 0xEAAA bytes to replace (but not actually replaced them).