If you export a simple table document with this library and attempt to upload it, it will be completely mangled. This can be fixed by changing literally anything and saving it in Word, thereby 'replacing' the document structure with a freshly saved Word generated one.
The problem lies in the document.xml structure. In other words, renaming both documents to .zip and extracting both, then replacing the 'broken' file's document.xml with the 'fixed' one will fix the broken one too.
The document.xml structure of the broken one
https://pastebin.com/raw/kaa3Erq5
The document.xml structure of the fixed one
https://pastebin.com/raw/mHn2QPK9
Here's an example of the broken docx upload
broken.docx

And what it should look like after making a small edit (changing 'Test Text' -> 'Test Text (edit)'
fixed.docx

I'm unsure how to make default exported documents compatible with Google Drive from the get-go or what's causing this issue.