I did a test with two different versions of Magento 2 and got different results on both. I did the test using Magento 2.3.1 and Magento 2.3.5-p1.
In both cases I placed an order with a Configurable product without anything special.
**Magento 2.3.1: **
Looking at the code, I noticed that this condition exists in the file "vendor\magento\module-quote\Model\Quote\Address\Total": Code Print
If I remove this "isChildrenCalculated ()" condition from version 2.3.1 the behavior is similar to 2.3.5.
From what I noticed it has to do with it ['product_calculations'] = self::CALCULATE_CHILD but I didn’t find where I configure it via the screen to change the behavior.
Does anyone know where I change this "product_calculations" value? Can anyone tell me why I have these two behaviors doing the same process in different versions?
PS: Sorry for link in images, i cant post image because of my reputation.