It took me a while to figure out why 128 worked at all (the script I thought was parser-inserted wasn't anymore at the point of test), and by that time I'd already added 151.
Note that the order of execution of scripts 2 and 3 is in flux (ref https://github.com/whatwg/dom/pull/1261), but it should at least be consistent between the 128 and 151.
It took me a while to figure out why 128 worked at all (the script I thought was parser-inserted wasn't anymore at the point of test), and by that time I'd already added 151.
Note that the order of execution of scripts 2 and 3 is in flux (ref https://github.com/whatwg/dom/pull/1261), but it should at least be consistent between the 128 and 151.