This has likely to do with the following (quoting from the Difference Checker documentation):
The special checkers are used for the cell contents as well as for the column domain (i.e. possible values and bounds).
The minimum/maximum values are obviously different in the reference and the produced table (edit to clarify: this has nothing to do with the actually visible values in the table content – but you can inspect it in the ‘Spec’ tab). To fix the test, you could make use of the Domain Calculator node. But you should probably double check, whether the domain information needs to be taken care of programmatically?
– Philipp