HTTP 400: Bad Request when using pagination

[jogga19]

I looked at "https://ogcapitest.ngu.no/rest/services/grunnundersokelser/collections/geotekniskunders/items?filter-lang=cql2-text&filter=harDokument.href%20IS%20NOT%20NULL" as an end-user, and found a bug with the pagination. Changing page works fine the first time, but it is then not possible to go to a another page without getting "HTTP Error 400: Bad Request". See attached screenshots. The problem is that "+" is replaced with "%2B" in the url.