The "old" version didn't have a test for the feature... the "new" version started with the tests for the "old" version... it was an easy thing to miss as a result.
As other threads have mentioned, a more advanced argument parser and detection of parsed, but unused arguments could have caught this. Of course, there's already complaints about the increase in size for the Rust versions of uutils, mostly offset by a merged binary with separate symlinks. It's a mixed bag.
But, I'm sure you'll be reverting back to Xfree86 now.
As other threads have mentioned, a more advanced argument parser and detection of parsed, but unused arguments could have caught this. Of course, there's already complaints about the increase in size for the Rust versions of uutils, mostly offset by a merged binary with separate symlinks. It's a mixed bag.
But, I'm sure you'll be reverting back to Xfree86 now.