Regions selection in nav bar mixes up entries

[pitpalme]

Describe the bug
Countries and regions are not display correctly grouped, but somehow mixed up.
We have 2 Germany, 3 Berlin/Brandenburg and all contain different locations/places.
It's confusing.

To Reproduce
See screenshots.

Expected behavior
Places shown grouped correctly, by areas and regions and countries.

Screenshots

[pitpalme]

Seems, we ran into a 16 year old, known, behavior:

REGROUP tag makes two groups with the same value

I think it works just as intended. From Django documentation:
Note that {% regroup %} does not work when the list to be grouped is not sorted by the key you are grouping by! This means that if your list of people was not sorted by gender, you'd need to make sure it is sorted before using it, i.e.:
{% regroup people|dictsort:"gender" by gender as grouped %}

Built-in template tags and filters: regroup

Note that {% regroup %} does not order its input! Our example relies on the fact that the cities list was ordered by country in the first place. If the cities list did not order its members by country, the regrouping would naively display more than one group for a single country. For example, say the cities list was set to this (note that the countries are not grouped together):