TYPO3 Core

We run into an Exception during rendering an Extension:

Uncaught TYPO3 Exception
Section "main" does not exist.

Actually something is going wrong during resolving the proper layout file.

Page Template

page.10 = FLUIDTEMPLATE
does use a layout "Default", with a section "content" (but no section "main")

layoutRootPaths is set properly in TS.

This is working just fine on almost all pages.

Plugin Template

plugin.tx_xxx does use a layout "Default" as well, however here we use a section "main" (but no section "content").
layoutRootPaths,and alike are set properly in TS.

However during rendering this extension for some weird(and yet unknown) reason the layout file from the page is used (which obviously is missing the section "main".

During debugging I found AbstractTemplateView of typo3fluid ll 190 through 200 responsible. $paths->getLayoutSource($layoutName) does return the proper source at first but however at some later point a wrong file will be served from cache.

The most weird thing, we use Layout Default for other extensions as well where we don't have this problem.

Templates and Layouts are all stored in a site-package (EXT:xxx-site)