TYPO3 v8.5 with Fluidtemplate and fluid-styled-content - Partials not working - typo3

Question

I use TYPO3 v8.5 with fluid-templating (with layout, partials and template) and fluid-styled-content.
However, as soon as I create a fsc-element e.g. text&media on my site, the partial files are ignored and only the section from the template file is output in the FE.
If I set the content-element to "hide", then the correct site-structure with partials were output in the FE.
My root-template is:
page = PAGE
page.includeCSS {
main = fileadmin/Demo/Resources/Public/Css/main.css
}
page.10 = FLUIDTEMPLATE
page.10 {
layoutRootPaths {
10 = fileadmin/Demo/Resources/Private/Layouts
20 = fileadmin/Demo/Individual/Private/Layouts
}
partialRootPaths {
10 = fileadmin/Demo/Resources/Private/Partials
20 = fileadmin/Demo/Individual/Private/Partials
}
templateRootPaths {
10 = fileadmin/Demo/Resources/Private/Templates
20 = fileadmin/Demo/Individual/Private/Templates
}
variables {
contentMain < styles.content.get
}
file.stdWrap.cObject = CASE
file.stdWrap.cObject {
key.data = pagelayout
default = TEXT
default.value = fileadmin/Demo/Resources/Private/Templates/DefaultTemplate.html
pagets__1 < .default
}
}
My page-TSconfig:
mod.web_layout.BackendLayouts {
1 {
title = Default Template
config {
backend_layout {
colCount = 1
rowCount = 1
rows {
1 {
columns {
1 {
name = Main Content
colPos = 0
}
}
}
}
}
}
}
}
DefaultLayout.html :
<f:render partial="Header"/>
<f:render section="Main"/>
<f:render partial="Footer"/>
Footer.html :
<div class="footer-container">
<footer class="wrapper">
Hier steht der Footer-Text
</footer>
</div>
Header.html :
<div class="header-container">
<header class="wrapper clearfix">
<h1 class="title">LOGO</h1>
<nav>
Hier erscheint die Navigation
</nav>
</header>
</div>
DefaultTemplate.html :
<f:layout name="DefaultLayout"/>
<f:section name="Main">
<div class="main-container">
<div class="main wrapper clearfix">
<article>
<f:format.raw>{contentMain}</f:format.raw>
</article>
</div>
</div>
</f:section>
Does anyone know this behavior and can give me a tip what's wrong with my code.
In TYPO3 v7.6 this code works fine.

Answer 1

There is currently an open bug (see https://forge.typo3.org/issues/77235) regarding this issue. Try to rename your Partials as a workaround until this is fixed.