layouts/partials/templates/css files not being loaded from sitepackage extension instead of tx-news original files

Question

I have a sitepackage that uses some modifications for bootstrap package that are properly loaded. However, any modifications to the news extension won't load from my sitepackage. Typo3 keeps loading the original files from the news extension. The files are defined in the constants.typoscript resp. in setup.typoscript of my sitepackage.

In TSOB, the configuration looks like expected and in accordance with the tutorials:

[view]
[layoutRootPaths]
[0] = EXT:news/Resources/Private/Layouts/
[10] = EXT:mysitepackage/Resources/Private/Layouts/
[20] = EXT:mysitepackage/Resources/Private/Layouts/
[partialRootPaths]
[0] = EXT:news/Resources/Private/Partials/
[10] = EXT:mysitepackage/Resources/Private/Partials/
[20] = EXT:mysitepackage/Resources/Private/Partials/
[templateRootPaths]
[0] = EXT:news/Resources/Private/Templates/
[10] = EXT:mysitepackage/Resources/Private/Templates/
[20] = EXT:mysitepackage/Resources/Private/Templates/

Another reference that is definitely not overrided is the link to css file.

[settings]
[cssFile] = EXT:news/Resources/Public/Css/news-basic.css

Should be mysitepackage/Resources/Public/Css/news-mods.css, which is defined in the constants.typoscript of my sitepackage.

I just found one working file so far and that is the mysitepackage/Resources/Private/Language/News/locallang.xlf in my sitepackage: any modifications to this one are properly displayed.

Has anyone experienced a similar situation with the news extension?