Hi, we've got a weird problem with confluence that i've been unable to find any solutions to:
When uploading (drag and drop) a document (word, powerpoint, etc.) into a confluence page, all text in the document preview (default "Files and images" macro) is replaced by weird symbols:

This happens regardless of font, the document contains standard latin characters only.
Uploading doc instead of docx results in the same garbled preview. When downloading the attachment and viewing it in word, it gets displayed properly.
When using the "Office Word" macro the text is displayed correctly.
We're using confluence v6.10.1.
Thanks for the help