Hello Christine S,
To resolve this permanently, place your cursor on the page where the numbering incorrectly resets (the start of the new section). Navigate to the Insert tab, click Page Number, and select Format Page Numbers. In the Page Number Format dialog box, locate the "Page numbering" section at the bottom. You will likely see "Start at" selected with a value of 1. You must change this selection to "Continue from previous section" and click OK. This modifies the metadata within that specific Section Break to look at the preceding section's ending number and increment by one.
If your document has multiple chapters or sections, you may need to repeat this step for every section where the numbering breaks. While you can attempt to select the entire document (Ctrl + A) and apply the setting, Word's handling of mixed section properties can be inconsistent, so manually correcting the "Continue from previous section" attribute in the specific headers where the break occurs is the most reliable method to prevent the numbering from reverting after a save.
I hope you've found something useful here. If it helps you get more insight into the issue, it's appreciated to accept the answer. Should you have more questions, feel free to leave a message. Have a nice day!
VP