OpenStudio Plant Sizing issue

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I have a primary-secondary chiller with common pipe simulation as can be seen below:

I want to have primary and secondary loops separated by an ideal heat exchanger. I created an empty water loop and moved my chiller and constant speed pump to its supply side. Then I added the fluid-to-fluid heat exchanger as below:

The issue is that the chiller size (autosize and same chiller) is twice as the previous configuration. I believe it should be the same. I appreciate if you got any advice for me.