TYPO3 Core

Hello,
I was struggeling with the problem, that some pdf-fhumbnails are not rendered in fluid.
for me the problem occured in fluid-template for the uploads-content-element (with bootstrap-package, but I'm quite sure that it comes from fluid.)

this fluid-snipplet generates all thumbnails (as far as I can see it by now):

<f:image src="{file.publicUrl}" alt="{file.alternative}" width="{settings.preview.width}" height="{settings.preview.height}" />

this renders most pdf-thumbnails, but some not:

<f:media file="{file}" width="{settings.preview.width}" height="{settings.preview.height}" alt="{file.alternative}" />

I guess it could have something to do with the pdf-frame problem which might not yet be implemented in the f:media-viewhelper?

with the best regards,
Sabine