shadydom css of one component leaks in other components in Edge18

I have ten custom elements with styles which acts as global in the document and then i am appending shawdowDOM in one component which i added another style(scoped style in this component),then i am importing pollyfills to make support with other browsers
it works fine with the native supported browsers but in edge browser v18 and chrome V49 and so on, the scoped style overrides the global style which is not the behaviour of shadowDOM

Start by reproducing the reported setup with ten custom elements and a scoped style inside Shadow DOM in Edge 18 and Chrome 49 using the polyfills. Compare the polyfilled behavior with native Shadow DOM; done means component-scoped CSS no longer overrides the other components' global styles.

Written by the indexing model from the issue text.