Created attachment 133830 [details] screenshot of arrow after saving. In Word 2010 (no other version tested) the signs "-->" are automatically substituted by an arrow sign (looks like →). If the document is opened once by LibreOffice Writer the arrow appears unchanged. If the document is changed, however, the auto-substituted arrow is changed into a different character (, it appears to be the unicode character U+F0E0). Another option is to insert a arrow character in Word 2010 via insert - special character. Arrow signs inserted that way remain unchanged. Arrow signs changed by LibreOffice do not only appear as "" in Writer itself but also in PDFs if saved so.
Created attachment 133831 [details] screenshot of arrow before saving opended in LibreOffice.
Created attachment 133832 [details] example document created in Word 2010.
Created attachment 133833 [details] Example document opened in Word 2010 which demonstrates how the arrow should appear.
Comment on attachment 133832 [details] example document created in Word 2010. The example file can be opened in LibreOffice. After opening the bug is going to appear.
Steps to reproduce are a bit muddled. Also, you don't mention the build of LibreOffice you are using. So it is not clear how you would have a Wingdings replacement from Word 2010. The LibreOffice Autocorrect replacement of the sequence "-->" is with Unicode codepoint 0x2192. But a 0xf0e0 codepoint is the Private Use from the Micrsoft Windgdings font. The codepoint is undefined for the Calibri font--and why there is a blank character there. The screen clips you provide show that font fall back is occurring as the Calibri font in the font drop list is italicized. So, assume you are on a Linux OS. When I open attachment 133832 [details] in LO 5.3.3.2 on a Windows 10 Pro system, the Wingdings PUA glyph shows. The font handling behavior on Windows has been reworked for the 5.3 builds. And believe if you set a font that is present in both Windows and Linux OS you will not have any issues with the fall back--or with export to PDF.
I am using LibreOffice 5.3.4 on Ubuntu 16.04. Please note that for reproduction it is not only enough to open the document but you have to save it and reopen it. I hope that made it clearer.
(In reply to marcus.knappert from comment #6) > I am using LibreOffice 5.3.4 on Ubuntu 16.04. Please note that for > reproduction it is not only enough to open the document but you have to save > it and reopen it. > > I hope that made it clearer. With document open in LO Writer, place your cursor after the replacement arrow (or missing glyph box) and enter the Unicode toggle <Alt>+x What Unicode point value shows? If U+f0e0, that is from the Private Use Area for what ever font was used. It is undefined in any but the original font--could be a missing block, could be a completely different glyph. If you want to maintain fidelity, you need to embed fonts. Or, more useful, simply be sure to use fonts that are found on all the systems/OS the document will be opened with. We can not do any better.