i did the durban from both sensi and dutch passion and the sensi version, altho looked very similar to each other, did have an odd taste...especially when compared to dutch passion's durban (an all-time fave of mine). i only did both that one year (also '99) and gave away the rest of the sensi d.p. but kept the dutchpassion durb around far longer...in fact just ordered another batch...
just to give you another idea for the possible answer...

btw...leaves will yellow (usually from bottom up) and drop off as the plant approaches harvest time...no worries...it's normal...