Shipping added to cart ERROR "free shipping" enabled

I have a very strange error that is easily replicated.
I'm working on a store and there is a Grouped (product with variants).
Variant 1 is set for "Customer Enters Price" shipping enabled "free shipping"
Variant 2 is set for "Customer Enters Price" shipping NOT enabled (digital download)
Variant 3 is set for "Customer Enters Price" shipping NOT enabled

If you add Variant 1 (with any price) to the cart NO shipping is required.
If you also add either Variant 2 or 3 (with any price) to the cart SHIPPING is NOW REQUIRED? The shipping estimator appears and shipping is required to complete checkout? How and why is this happening? NONE of the Variants require shipping!

It seems like any cart that has a "free shipping" item & non shipping item in the same cart is being charged shipping. This is happening with all the products not just the example product. This was not a problem on version 3.70 just 3.90 since we upgraded last week. This seems like a big bug.

Here is the sample Grouped product I used in the example.
http://www.jerrysavelle.org/store/august-2017

Please help.

Allshookup wrote:

With only variant 1 (August 2017 - CD) in my cart, as guest, I see shipping as required.  Can you provide further repro steps?

How is that even possible?
I have Shipping Enabled and the checkbox for "Free shipping"

Maybe there's something I'm not understanding - "free shipping" implies the item needs to be shipped but at no cost.

I understand the "Free Shipping"
But why if item 1 has "free shipping" and item 2 has NO shipping (digital download) people are being charged USPS Media Mail Parcel ($3.13)

I see now.  Do you have access to the source code?  The bug is on line 802 of OrderTotalCalculationService.cs - you'd change this:

  if (cart.All(item => item.IsShipEnabled && item.IsFreeShipping))
                return true; 

to this:

  if (cart.All(item => !item.IsShipEnabled || item.IsFreeShipping))
                return true; 

Thanks for reporting this!

*edit for formatting

Thank you for your help. I was hoping your solution would fix the problem but after making the changes to the code I still get the same shipping charge showing up.

Your code is incorrect.  Please simply copy and paste.

YES! I just noticed that as well! I will update and test again.
Thank you.

Also I have opened an issue about it: https://github.com/nopSolutions/nopCommerce/issues/2504