The validation tests in this one include a separate "all numbers are the same" case, whereas the debugging ones don't. Though there are duplicates in the last case, the large entry.
This ended up very confusing for me when my bash solution kept timing out on the large case: it was a trivial bug that could be fixed in a few characters, but I spent a long time looking for performance improvements that weren't actually needed. (Those who solved the more complex problems in bash know what I'm talking about!)
I'm sure many future problem solvers would appreciate having a dedicated "duplicates" case separate from the large data set.
Or at least having this reminder in the forum that it's worth testing for.