Another gamma question

[DIO]

I´m having a gamma issue in 2.11.1a. I´m pretty sure I didn´t had that problem
in older versions of octane.
I´m rendering as an openExr without the octane tonemapping. 3dsmax gamma 2.2 is enabled.
When I render via the octane render viewport everything looks fine. I can port it to max frame buffer
and save it as .exr with automatic gamma in 3dsmax save dialog.
But:
When I render the image via the 3dsmax render dialog it looks correct while octane is still rendering.
As soon, as the sample limit is reached and the render is finished (in the moment the image is saved) it jumps to a brighter incorrect gamma.
So also the render image saved is incorrect, no matter what gamma I put into the 3dsmax save dialog.

It is impossible for me to get the correct result through 3dsmax render dialog, only the dublicate of the
octane render viewport creates the right result. Why is that?

Can anyone help? What am I missing?