Where to manage cache setting for documents opened in OWA?

I have a few thousand .docx documents which contain a field in the header which displays only on printing of document, not viewing.  On first print, header works as designed printing “Information contained in this printed document valid for 24 hours from print time of M, dd/yyyy HH:MM:SSS”.  However if another user prints this document within the next few hours, their header does not update the date/time field.  This seems to be a caching issue as eventually the field will update.  I haven’t been able to pin it to a specific hour or cache size setting.  Ideally all documents in this library should not cache.  I am hoping someone can lead me to the proper place to manage this setting.  These are Policy & Procedure documents and are to open in the OWA browser and with IRM they are only able to view and print. Any advice is greatly appreciated!