Ctexmap element brigher in 1.5 than in 1.4

In 1.5 Ctexmap (ambient occlusion) is very bright comparing to 1.4.1.
Gamma issue?

Any example of this or instructions how to reproduce?

First one from 1.4.1 (gamma automatic) (resolution reduced)
Second one from 1.5 (gamma automatic)

I didn’t change properties of dirt in AO, just installed the new version and clicked render.

If I want it looks like first one, I need to store it with gamma override = 1.0