They have forgotten all of Sharpe's scars from previous battles in the previous movies.
There is a Continuity error which was addressed by Sharpe TV Series Director Tom Clegg and writer Russell Lewis as being Non Canon. Sharpe's wife Lucille who's erroneously reported as deceased in Sharpe's Challenge is in fact still alive and married to Sharpe living at their house in Normandy with her son Patrick Henri while he was away in India at the time of Sharpe's Challenge.