While relapse of Hep C is a possible cause of abnormal liver function following DAA treatment there are people who attain SVR (ie no Hep C) but still have elevated values.
For some cirrhotics complete normalisation does not always happen but for people with lesser degrees of fibrosis there is probably another reason, ie 2 diseases have been present causing the liver function abnormalities and we have only diagnosed and cured 1. In other words we have been blaming the Hep C when there is in fact another disease present.
The list is quite long. Hep B reactivation and Haemochromatisis are relatively common and easy to rule out, but then we move on to less common causes. Here is a full(ish) list: