The symptom is specific: old article URLs redirect to the homepage. Start with the affected item and identify the decision or input that could produce this behavior.
Find the likely cause
The migration used one catch-all destination.
Treat this as an explanation to verify against the actual work. Look at the input, the relevant decision, and the final result together. If the evidence does not support this diagnosis, investigate the mismatch before applying a convenient but unrelated fix.
Make the targeted correction
Map valuable old URLs to relevant equivalents when they exist.
A redirect plan should preserve the visitor's intended task when a URL moves or a useful equivalent replaces it.
Check that the repair worked
A visitor following the old link should find the expected subject.
Repeat the check on the final version that the reader or customer will encounter. An approved draft, a preview, and a published result can differ; the acceptance decision should concern the version people actually use.
Prevent the next related failure
A separate issue to watch for is this: redirect chains grow after repeated migrations. Update mappings toward the intended final URL where feasible.
Monitor the useful outcome
Track broken destinations, redirect chains, and successful access to important migrated content.
Keep a short record of the original symptom, the evidence behind the diagnosis, and the result of the acceptance check. That record makes the solution reusable when the same condition appears again, without assuming that every superficially similar problem has the same cause.
Official reference for the platform or standard discussed: Google Search Central: site moves.