Using version 4.2.5.2 when a .docx file is loaded the text isn’t visible. File extension .ods, odt, and .doc. load correctly. Installed version 4.3.0.4 with no change in results. The number of words and characters at bottom of screen and the file name at the top of screen appears to be correct.
Which OS are you using? How do you open the files? Side note: In LibO 4.2.5.2 I had no problems; same with 4.2…6.2.
Support for the OOXML file format is incomplete. List of open bugs for “docx” can be found here see if you can find one in that list that describes the problem you are having (or edit your question to more accurately indicate the nature of the problem). Also note this.