No updates if only difference is in TTL.

[magior]

If the only difference in one record is in the TTL the nsupdate file isn't populated with "update add" command and Puppet keeps notify the difference on any run.

I think that inserting a check and returning newdata on rrdata_adds if @properties[:ttl] is not empty could be a possible workaround.
Something like this on nsupdate.rb:

if (@properties[:ttl] == nil)
resource[:ensure] === :absent ? [] : newdata - rrdata
else
resource[:ensure] === :absent ? [] : newdata
end

[jcharaoui]

Tested and works for me!