In practice
Find it by grouping Search Console queries by page: a query that swaps between URLs week to week is the signature.
Fix by consolidating into the strongest page and redirecting the rest, or by re-scoping each page to a distinct intent.
Why it matters
Split signals mean split links, split engagement and a lower ceiling than one strong page would have.
It usually comes from publishing without a plan, so the fix is editorial as much as technical.