Lane three of three was closed on the southbound carriageway after a collision at junction 25 for Brynn.
The collision happened at around 4.30pm on Sunday (September 8).
Highways England reported severe delays back to junction 27 for Standish, with delays of 30 minutes expected traffic conditions.
At 5.35pm the incident was cleared and traffic was flowing freely, but normal traffic conditions did not return until around 6pm.
The junction 25 entry slip road was closed from the A49 due to the incident.