Faint smell of soy sauce?

Hoping it is the power of suggestion...

I bottled my oaked imperial stout tonight, oak chips were soaked in BenRiach 12 year old (VERY peaty single malt Speyside). It spent about 3 weeks in primary (first week of August), then I racked to secondary and left it for 5 or 6 weeks and bottled tonight. I used WLP004 for my yeast, and it was a mini mash.

After bottling, my wife took a taste of some of the stuff that had spilled on her hand while bottling and commented that it tasted kind of like soy sauce. She may have been just making it up, I'm not sure. I tasted some and it was definitely not salty, nor did it taste anything like soy sauce, but the smell had a faint trace of soy sauce. The color is the same as well, but the color is where I want it. Is my mind just playing tricks on me, or is there a possibility that one can induce soy sauce like aromas or flavors in a beer? Some of the yeast cake did go into the bottling bucket, but I don't think that would cause any off flavors. Guess I just have to wait it out for a few months, maybe

I've actually heard people use "soy sauce" as a descriptor when sniffing/tasting peaty Scotch. I'm guessing it's the whisky.

Even if you don't notice those soy sauce notes in BenRiach normally, something about the way it mixed with the beer could have brought it to the forefront. The toast from the oak cubes is probably accentuating it as well.

I had similar flavors in the first 2-3 stouts I made. It went away with time and I've changed 2 main factors since last stout season - filtered water and adding dark grains during the sparge. The 2 stouts I've made so far this season don't have the same off flavor.

What's your water source?