I didn't start lurking here until 2015 so the OP predates my arrival.
Two I know about for sure the 750 ACE and the 650 Hawk GT both fire on the exhaust stroke and both will still run fine, but sound weird with one of the camshafts 180 degrees out.
Of note is the fact that the ACE has common connecting rod journal alignment and the Hawk GT is offset both are single ignitor/pick-up, notched reluctor setups, the ICM units are different obviously.
I'm guessing the ICM being crank triggered can't be bothered to sort out which stroke is which and fires every revolution.
So ask me about others like the VT600C and all I can do is guess, I'd guess they all behave the same, but I would not advise somebody's tachometer purchase based on my guess.
It is good to hear that at least some of the VT600 years behave that way too.
The fuel injected bikes may be smarter with more sensors and a more precise brain box, what's the guess on them?