Summary

Get group memberships for user does not evaluate start query parameter properly. The start value reflects in the response but the result set is the same all the time.
 

Steps to Reproduce

1. Get the user key of a user who is a member of multiple groups. In a dev cloud instance, the admin is by default a member of confluence-users, jira-servicedesk-users, and jira-software-users.
2. Make a request for their groups using the /memberof endpoint (/wiki/rest/api/user/memberof?key=admin). You will get a list of their groups, which in my example is the three mentioned above.
3. Add the "start" query string parameter (/wiki/rest/api/user/memberof?start=1&key=<userkey>).

Expected Results

The result set should start with the value supplied in the start query parameter.

Actual Results

The start index is always ignored and it returns a list of groups as though the start index was 0.