Version of Adobe InDesign, InCopy or InDesign Server
InDesign 17.4.2 / 18.3 (identical behaviour)

Steps to reproduce the issues

Create a Word document in .docx file format, add some text and some index entry fields, then a hyperlink at the end
Save file and place in InDesign

Expected result
Document is imported and hyperlinks remain in the same place

Actual result
Document is imported and hyperlinks are shifted backwards by 1 character for each index entry field.

The error occurs regardless if you place the document into an existing text frame or create a new text frame by placing the document.

This renders existing hyperlinks in a document completely out of place and unusable, especially for later EPUB exports.