Kershaws Brigade and the 2nd SC were transfered out of Virginia in January 1865. They then had service around Charleston, then up into NC. They also fought at Bentonville (NC) in March 1865. One of their brother units in the brigade lost a flag there (15th SC), Surrendered along with the AoT at Durham.
Thus after January 1865 (Kershaws Brig/2ndSC) were recorded as no longer being present with the ANV, Dept of Richmond, Trenches of Petersburg etc... Hense when the unit is known to be present and serving in one region, then a flag reportedly contributed to them is said to have been captured far away at Saylors Creek in another theater of operations within the same time line.
It would be a natural suspicion that whichever flag is reported to have the 2nd SC Inf & Saylors Creek relation would be a bit suspect of its unit ID, or the actual time/place of capture, or the circumstances of its capture (found in a baggage wagon, personal stowed belongings, etc)
What is known as Kershaws Brigade itself was recorded not present at Saylors Creek. However Gen Kershaw himself by this time was a Division commander, and he continued to serve the ANV theater till the end including Saylors Creek. If the Saylors Creek associated flag was noted as being captured from a unit then in Kershaws "Division", that would be historically feasible.
Just an opinion and observation
Frederick