Why is Heist DLC Content Not Appearing in Singleplayer?

[Boomer8]

So I downloaded Heists DLC today and I wanted to check out my singleplayer game since R* services were unavailable. The message appeared that "new vehicles had been added to your garage and air hangar" but when I checked them they weren't there. Am I the only one experiencing this?

[Johan]

For now there's no word on any of the DLC appearing on SP... not sure if it's just a glitch or if there really isn't anything for those SP lovers this time.