It looks like you are hitting the default limit that is outlined in the API Documentation, Jive REST API v3.14 :
The max number of items returned per page. Usually set with the
countquery parameter. Most paginated results default to 25
itemsPerPageand can be set as high as 100 with the
If you want to adjust the default, the system property for this setting is jive.api.result.count.override. It is not recommended to set this setting beyond 100. If you are a cloud customer, you will need to open a support case within your secret support group.