Overwriting theme wierd behaviour

There is some weird behavior when overwriting theme files…

Example:
platform/src/Storefront/Resources/views/storefront/page/content/index.html.twig
by this one
custom/plugins/MyTheme/src/Resources/views/storefront/page/content/index.html.twig
The Symfony Profiler will return @Storefront first, instead of @MyTheme