If it will not hold changes that you are making and you are saving those changes to the template, something is preventing saving changes. The most likely culprit is a poorly-written Add-In program. The ones that have been popping up on the forum for doing this lately have related to bluetooth, but it could be anything. See Enable or disable add-ins in Office programs - Support - Office.com.

One workaround is to directly open the normal template and save your changes there. Do not add any text (including headers, footers, or page numbers) to the normal template. Normal Template in Microsoft Word - How to Open