There's a difference there; Austria-Hungary was a real union unlike Sweden-Norway, being a personal union. Essentially a developed personal union where the junior partner's sovereignty has been limited even more to point you can't really call it a country anymore.
To add to this; this was quite the bizarre situation:
While the rest of Switzerland were cantons under a republican government, Neuchâtel however, retained its traditional monarchy. Between 1708-1806 and 1814-1848, the area was also in personal union with Prussia. It was overthrown through an revolution in 1848 and Frederick William IV of Prussia only relinquished his claim to the area in 1857.
Very confusing, but I hope this clears it up more.
While the rest of Switzerland were cantons under a republican government, Neuchâtel however, retained its traditional monarchy. Between 1708-1806 and 1814-1848, the area was also in personal union with Prussia. It was overthrown through an revolution in 1848 and Frederick William IV of Prussia only relinquished his claim to the area in 1857.
Very confusing, but I hope this clears it up more.