Overwriting page.logo.normal dynamically depending on site configuration

I try to overwrite the page logo dynamically depending on the site-configuration (each site has a defined `tx_myext_organization` record which itself holds various information such as a logo):
```
lib.organizationLogo = FILES
lib.organizationLogo {
references {
table = tx_myext_organization
uid.data = site:myOrganizationUid
fieldName = logo_original
}
renderObj = TEXT
renderObj {
data = file:current:publicUrl
}
}
page.10.dataProcessing.1553883874.files.normal = lib.organizationLogo
page.10.variables.test < lib.organizationLogo
```

Not sure if the `BK2K\BootstrapPackage\DataProcessing\StaticFilesProcessor` is the problem here, but `file.normal` contains the string "lib.organizationLogo" during debugging instead of the file URL, so it seems the expression is not evaluated (also `normal.data = ...` does not work). Printing the `test` variable in Fluid contains the correct file URL.

Can someone relate to this issue?