Style Mapping has gone nuts for me in 17.2 all mapping from Word 365 from Mac after mapping just goes to basic paragraph. Checked with 16.4 and mapping works as expected. So seems to be a big bug in 17.2
If so - try exploring the 16.4 version from InDesign to IDML.
Open the IDML in 17.2
Save as a new file.
Does the issue persist?
If a document is not behaving well then try
Open the IDML in InDesign Save the file as a new InDesign file with a new name See if the issue persists.
Try resetting your preferences: The easiest way to reset everything is to delete the InDesign preferences: as soon as InDesign starts to boot hold down Shift, Alt, Ctrl (and Apple/Cmd if working on a Macintosh). A dialog will appear asking to delete the InDesign Preferences, select 'Yes' on this dialog. Further info and instructions here if needed: https://helpx.adobe.com/in/indesign/kb/indesign-preferences-support-file-locations.html