Macros can't use fractions of seconds. You'll have to put /wait 3 in there or it rounds it down to 2 I believe. That's not to say Scourge isnt bugged of course, it may be, but try with a 3 first.

It's generally a very very bad idea to use GCD skills in macros though - you can't queue them up by pressing the skill in advance and it will result in a DPS loss as you'll have spaces between your skill use (the 3 second wait between fracture and scourge necessitated in that macro alone will add 0.5 secs onto your rotation).

It's best to just keep them on separate buttons. Also, I've not done the maths on DRK (just PLD), but is Fracture actually worth using? It's only a 220 Potency attack in total if it ticks for the full 18 seconds, for a huge 80 TP. You might find it better just not to use Fracture as a crossclass skill and take some of the extra tanking cooldowns instead.