Saw exactly the same thing last Tuesday evening on a Monarch A321 just after landing at Tenerife South. Several Russian speaking people got up and were shouted at by the nearest CC very loudly and assertively "Sit Down" several times. They did.
Saw the same thing last month on landing at Dallas, Fort Worth on a BA 777. A very loud sit down from the nearest CC, who when she was released immediately went over to the lady passenger and very calmly and reassuringly said everything was ok but she must remain seated until the sign is off etc. She even patted the lady's shoulder to continue to reassure her.
Very professionally handled in both cases.