Paging does not give "next" page up to 100000 features?

[wokseb]

I would assume this request for example would be entitled with a link to both a previous and a next page. However, only the previous is supplied.

https://sosgeo.artdata.slu.se/geoserver/wfs?REQUEST=GetFeature&OUTPUTFORMAT=application%2Fjson&VERSION=2.0.0&TYPENAMES=SOS:SpeciesObservations&COUNT=5000&SERVICE=wfs&CQL_FILTER=isRedlisted='TRUE'&STARTINDEX=9950

I seams lite there is also a limit of 10000 and not 100000? Nevertheless the request below still works, but is not as failsafe to manually increment the startindex.

https://sosgeo.artdata.slu.se/geoserver/wfs?REQUEST=GetFeature&OUTPUTFORMAT=application%2Fjson&VERSION=2.0.0&TYPENAMES=SOS:SpeciesObservations&COUNT=5000&SERVICE=wfs&CQL_FILTER=isRedlisted='TRUE'&STARTINDEX=14500

Clarification: StartIndex 5000 gives a next-link in the response while StartIndex 5001 doesn't.