If using server side mode, and your columns's data is specified with a function, I've found that when you call ajax.reload() on your table, it calls that data function on the old data before calling it on your new data.
Here is a jsfiddle example https://jsfiddle.net/anneb574/1o6mtwxc/23/
I have made it so that whenever the data function is called, it logs the id of the row, so you can see what it's being called on.
If you go to the second page of data, and click the reset button, you'll see that the function is called on the page 2 data twice before being called on the page 1 data.
This seems fairly harmless, albeit inefficient, but my setup is a bit more complex and it's causing issues for me. (basically, I have a complex data layer providing data to the table, which my column's data fn needs to access, but with extra calls to data that no longer exists, I have to add more logic to prevent errors)