Hi Daniel,
From my understanding as long as the 2 variables are set the same it should never have a duplicate so, yes changing it should fix it. However, if the numbers are too big, it might cause an export failure. The limit is environment specific so you would have to experiment with it.
The reason why the issue happens for example is because lets say it is set to 250 and 500. It grabs records 250 at a time max of 500 records. So if you have 500 or more records it will grab it twice. So for instance lets say you have tickets
500
....
1
The first grab would be
500
...
250
If someone creates a ticket in the meantime you would now have tickets 501...1. So now the 2nd grab would have 250.....1 as the first grab technically would have been 501...251. So now you see a duplicate of 250.
This is kind of what I get from the KB article...
When a list of records (example list of incidents) - CA Knowledge