Loss of partial editing area

From time to time I find that I lose square km’s that I have previously driven in my total area of editing area. This means that I have less editing coverage, and hence less ability to improve the map and also less ability to increase my point score.

I am unsure why waze would delete an editors square km’s after a period of time, when it affects their ability to edit the map.

Has this happened to anyone else? How can I get this reversed?

As defined in this Waze Wiki page,

You can always apply to be an Area Manager.