I'm using v7.1.5.2.
In the Scene Editor, the text is correctly shown when italicised. When opening the scene in my default RTF Editor (MS Word, in my case), the text also shows correctly when italicised. When applying italics, I apply it via the Font options (or by hitting CTRL+I).
I recently started using the Export Project to Docx format to supply me editor with Word copies for editing/proofing. However, I found that the export doesn't always honour when Italics are applied to text so text that should be italicised isn't in the exported Docx file.