DRESP2 stress not equal with DRESP1 stress

Hy,

I would like to calculate a special safety value from stress responses, and using it in topology optimization.

The test of this calculation is started with a simple problem.
DRESP1 case 1:
- constaint: DRESP1 (von mises stress response, one selected element)
- objective: DRESP1 volume 
DRESP2 case 1:

- only response: DRESP1 (von mises stress response, one selected element)

- constaint: DRESP2, (equation response) is calculated the following equation a(x)=x and using the DRESP1 von mises response
- objective: DRESP1 volume 

In this case the changes on design variables are the same, and the results are the same. /emoticons/default_smile.png' srcset='/emoticons/smile@2x.png 2x' title=':)' width='20' />

Than i changed the response element quantity to 2 and the DRESP1 and DRESP2 case results are different

I have tried to change constraint screening, nothing has changed
I have tried to look on sensitivity values, but no stress values included in *.asens files or *_topol.h3d files

I have tried to compare it with displacement response/constraint and they are good, so the DRESP1 and DRESP2 with 2 response nodes has the same results.

Is this problem connected to Stress-NORM aggregation ?
How can i turn ON Stress-NORM aggregation in DRESP2 case?
How can i examine the stress response sensitivities?
Did i miss someting in the setup?

I have attached the 2 different *.hm and *.fem files

Thanks,
CSR

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