I've just done some experimentation with the latest version of the Hack font to see if I can reproduce this issue.
I haven't had any luck in getting it locked into italic, but I am seeing some very strange behaviour.
If I select the font using the font dialog, clicking OK, then go back in, there are no options for choosing a font style other than regular. If I then click another font and go back to the Hack font, suddenly there are bold and italic options. I note that this is again different from what you're seeing in your screen capture, where you have regular and bold options but no italic. I'm encountering this same issue when using the font in Notepad too (with no NCrunch involvement). I think this font may have a few problems.
Can you confirm whether downgrading your NCrunch resolves the problem?
Note that the chosen font style is stored inside the C:\Users\USER\AppData\Roaming\NCrunch\globalconfig.crunch.xml file. It should be possible to override the behaviour of the font dialog by editing this file manually (with your IDE closed).