v:content.render does not respect fallback

[rutschmann-BIZ]

Example:

en-DE base is sys_language_uid 0
de-DE base is sys_language_uid 1 / fallbackType: fallback / fallbacks: '0'
en-AT base is sys_language_uid 2 / fallbackType: fallback / fallbacks: '0'
de-AT base is sys_language_uid 3 / fallbackType: fallback / fallbacks: '1'

Startpage has a footer, startpage is translated to all4 langauges.

Subpage shows footer content from startpage (formerly known as slide="-1").

Problem 1:
Not translated Pages in de-AT point with v:content.render slide="-1" to content from de-DE of the startpage, instead of the content from de-AT from the startpage

Problem 2:
If the page is translated (only page, not content) v:content.render without "slide=1" points to en-DE instead of de-DE.