Soy sauce off flavor/aroma

[BrewBama (Dwain)]

Soy sauce stout

I brewed a milk chocolate oatmeal stout on 10/24 and today 11/6 I transferred the batch to a secondary. I tasted some of the beer and it taste like soy sauce. I was wondering how this happened, or causes for this. I mashed in low but raised the temp to 152* and used dry yeast, Windsor from Danstar/lallemand. The beer fermented between 63-68* which is my house temperature. And it looked to have completed fermentation in 4 days. I rehydrated the yeast and used two packs because I was shooting for…