Is Soros' theory of reflexivity aligned with normative vs positive economy dichotomy?
I would say there is some degree of correspondence between the two dichotomies. However, in the economic side of things, there is in my opinion a much clearer relation between positive and normative economics (at least in the theoretical side), as it is through the use of positive economics that normative means are supposed to be achieved. 

The other dichotomy however seems to be less formal in this relation. Individuals or agents can have a given understanding of the world, but this might not be correct, or precise. Thus, if they base their manipulative actions based on their perceptions of the objective reality, it does not necessarily mean they are using the correct map of reality to act upon it. 

In other words, positive economics is (allegedly) science, whereas agents cognition is not necessarily (and perhaps not mainly) built upon scientific knowledge.

Now, having said this, it is also debatable that the normalite-positive dichotomy is as clear as initially theorised by Milton Friedman in his 1953 book "Essays in Positive Economics". For example, some Marxists argue that science itself (at least social sciences) is part of the tools used by the ruling/capitalist class to exert control over society.
In philosophy of science, there has been a long debate about what science is and about whether there is such thing as "scientific progress", or whether science is just ideology (for example, see here).