us-05 problems

[grommit420]

hi guys long time lurker first time poster. i need some input on a problem i`ve been having with us -05 on my last couple of batches. they seem to develop a very strong sulphury\alcohol taste over time. the taste is nearly undetectable when coming out of secondary you might get slight hints of it but nothing more but after bottling it seems to get worse with time making it completely undrinkable after 2-3 months sometimes even earlier. i've brewed a couple of batches under the same conditions but with s-04 and came out as clean as could be and even benefited from being bottled for a while. i'm kind of at a loss here on what to do i have a cream ale extract kit waiting to be brewed but comes with s-05 and i really dont wanna end up with another undrinkable batch. as for the fermenting particulars i do not rehydrate i direct pitch in the wort, i ferment at around 64f +\- 2f ( i use a temeperature controller hooked up to a heat belt ) and usually leave in primary from 7 to 14 days depending on airlock and hydrometer reading usually i'll only put it in secondary when there is no or very little arilock activity even if the hydro readings are telling me its fermented out. and then transfer to secondary for a week or two for it to clear before bottling. i use star san everywhere and wash out all my equipement in it and use r.o. water from local home brew supply. what am i doing wrong!!