My area_chart is only showing one feature from my dataframe at a time for every refresh

I have a dataframe with two columns, my area chart is supposed to show shades of two colors, which are specified in the legend, but only one color/column displays and it switches after every refresh. here are my codes:
#function to load the data
def load_actualVpred(nrows): #nrows is number of rows
actualVpred = pd.read_csv(‘ActualVpred.csv’, nrows = nrows)
return actualVpred
#load data
actualVpred = load_actualVpred(50)

#visualize the data
st.area_chart(actualVpred)