Yeah you’re right on that one. My bad.
Looking at 4.14 preview 1, though, there has been improvements over 4.13’s and this still appears to be intended that Gamma relies on Bloom to be enabled in some form.
In 4.13 there was a noticeable “pop” when you have Gamma values with a Bloom value between 0 and 0.0001. In 4.14 and my internal 4.15 build work exactly the same. Gamma and the other options under Color Grading also have slider values for white level now as well. With the scalability between medium and low, there is likely another cvar that is being set that’s just not mentioned in the documentation, but I’ve not looked through the source yet. If you need Low settings and this enabled, I would say as a workaround to just use a very low-value Bloom to keep the gamma.