Unlike other services, attempting to clone RunService results in no error, however the result of cloning will always be nil regardless of the Archivable property.
local runService = game:GetService("RunService")
print(runService:Clone())
nil
runService.Archivable = true
print(runService:Clone())
nil
Instead I would expect the same as attempting to clone any other service
game:GetService("CollectionService"):Clone()
00:00:00.000 - CollectionService cannot be cloned
Obviously you should not be cloning services, but this is inconsistent with the rest of the API. If you’re working on any sort of system that recursively clones an instance then this could be an issue.