Theme of Fiori reuse library

We meet a problem which is related to the theme of our fiori reuse library:

We receive a ticket 1580024800 2015 report that, when launch our app Sales Pipeline, the background color is white and correct:

Then navigate to My Opportunity app(cross app navigation) by click an opportunity link on the bubble details, please notice this My Opportunity app depend on a reuse library:

Then click back button to navigate back to Sales Pipeline, all the functions are OK but the background color turns to grey:

We checked and find that the grey color is from our reuse library during the navigation:

1.   When launch Sales Pipeline the first time, the background color css refer to @sapShell_Background and its value from fiori blue crystal theme:
   

2. When navigation happens, it get background color again from reuse library and overwrite the white @sapShell_Background value to grey(happens when init navigated target My Opportunity):

We think the reason probably the @sapShell_Background value is not correct in reuse library:
We checked with the build target file of our reuse library, there are two folders under theme folder, the sapShell_Background value in library-parameters.json are grey in both folders:

Here we think the color in sap_bluecrystal should be white(#ffffff)? The same as the color in blue crystal theme of ui5 core library? But we cannot be sure since we are not familiar with how it build.