TYPO3 Core

TS-Setup for page.config:
-------------------------

  // Language Settings
  uniqueLinkVars        = 1
  linkVars              = L
  sys_language_uid     = 0
  sys_language_overlay     = hideNonTranslated
  sys_language_mode     = content_fallback
  language             = de
  locale_all           = de_DE.UTF-8
  htmlTag_langKey      = de

// Condition to set language according to L POST/GET variable
[globalVar = GP:L = 1]
config {
    htmlTag_langKey         = en
    sys_language_uid         = 1
    language             = en
    locale_all             = en_UK.UTF8
}
[global]

Affeeted extensions i'm using
------------------------------
tt_news-version 3.4.0 Beta (most recent)
extbase-version 4.7.7 stable
tx_realurl-version 1.12.3 stable (currentyl disabled but doesn't seem to be the issue trigger)

Situation:
----------
System is configured for multilanguage (default german and id 1 english) purposes. Translated default content and templavoila content is displayed correctly at the frontend. Every page or sysfolder has a page_language_overlay record for english translations. News records are translated, also all records for my own extension. No translation is visible in frontend; exceptions: my own extbase extension displays translated records only when in showAction()-mode, listAction is not displaying translations.
In general, neither tt_news nor my own extbase extension renders at least as the extension wrapper at the frontend when english is chosen. Strange fact: the extension 'formhandler' (extbase extension) works in every which way.

I have tried so much and I don't have any explanation for the issues; I am likely to think that there might be a bug according to extension translation handling or something like that.

Greetings,
Martin Sauerbrey