Full tree seems to rerturn partial results

[Pooya-Oladazimi]

Describe the bug
Full tree button returns only partial result when used on this: https://service.tib.eu/terminology/ontologies/eclas/terms?iri=http%3A%2F%2Fdata.europa.eu%2Fbkc%2F001.04.06.0050&lang=en

The API call for it is: https://api.terminology.tib.eu/api/ontologies/eclas/terms/http%253A%252F%252Fdata.europa.eu%252Fbkc%252F001.04.06.0050/jstree?viewMode=All&siblings=true&lang=en

this seems incorrect since the onto has 999 root terms but the above only has 100 results: https://api.terminology.tib.eu/api/ontologies/eclas/terms/roots?page=0&size=10000&lang=en

To Reproduce
compare the number of root terms and the number of results in the full-tree