Tested with NuGet CLI 4.3.0
nuget list -Verbosity detailed jquery -Source http://localhost:8081/repository/nuget.org-proxy/
pages results 3 times
nuget list -Verbosity detailed jquery -Source https://www.nuget.org/api/v2/
pages results 40 times
Attached is a charles capture showing both commands for comparison against Nexus 3.6.0.
There should be no difference in results paged through for identical queries.