Working in a linearized Color Space in After Effects causes hard gradients
I use the trapcode suite as well, the issue has more to do with the fact that even though you may be working in an sRGB workspace at 32 Bit; your monitor output is 8 bit. 10 Bit monitors are available but unless you forked up a lot of cash - you are viewing 8-bit. 

The way to solve gradient problems like this - with this as well as any other gradient in AE/Premiere/PS; is to add an adjustment layer to the top of your project; on top of all layers. Add the standard NOISE filter. Check monochromatic (or un check use color noise) - you don't want color. Gaussian sometimes looks better; it's one of two options on the NOISE pop-up. 

Typically; I use a setting of 2 - 4%. But it really depends on your comp settings. If I'm working with RED 5k footage I typically have to do 1-2%. 

Lastly; honestly I almost always add NOISE to all the work I do; even if it's just 1% on a nested timeline for output. It solves a lot of aliasing problems and is a standard trick in post many people use. 

Hope that helps.