> In essence, it's advisable to take the paper’s reported figures with a grain of salt, particularly as they cannot be precisely reproduced as described. Nonetheless, this approach continues to deliver unexpectedly well.
A "grain of salt" is different from "critical evaluation flaw," and if the reproduction's results are true, then the method doesn't after all "deliver unexpectedly well".
https://kenschutte.com/gzip-knn-paper2/
This paper isn’t any surprisingly effective result. It’s thoroughly shoddy scholarship by which the authors should feel embarrassed.
I mentioned it towards the end, in the 2nd last paragraph. Those issues in the evaluation do bring its accuracy down a bit, even then it performs better than expected, considering it is doing knn on compressed data.