Transparency without Flattening
Sorry for external reference links!!!!!
As mentioned in the below Adobe help page, When we choose the Adobe PDF 1.4 (Acrobat 5.0) or later version transparency will be retained in the PDF.
Flatten transparent artwork in Adobe InDesign
But now with I am in same situation as in below thread,
High resolution PDF still generates low resolution drop shadows?
My original question is,
My export preset looks like below, and the transparency flattener is disabled. But indesign produced the flattened transparency output with PDF version 1.7.
Can some one help me to understand whether it is a bug in Indesign cc 2017 or do I need to enable/disable anything else in preset/preferences to get the PDF without flattened transparency ?

