docx file mime wrong type back getMimeType

I using CI 4.3.2. Tested on Debian 11 (php 7.4) and Debian 12 (php 8.2).
Simple way for get error:

1. open libreoffice writer and write single word "test1", save in docx format (getMimeType work as expect).
   
2. add picture in document and save document (getMimeType don't work as expect I got "application/octet-stream")
   

Example of file can download from link - test1.docx