A nic concentrate in 100mg can have a pretty noticeable odor, especially if it's been hot and it's got a little oxidized...
Generrally, the smell can have leftover notes from the source material(tobacco), which is in most but the very cleanest nics, I think, and that note is a very special dark rich pungent nutty woody damp tobacco'y smell.
Other than that, then there comes the actual pure nic odor, which is additional in above mentioned nic, and the only note in very pure nic, and that is a, too me, acetone smell and also a little fishy(normal, not bad! Read it up...)...
These above mentioned notes, are normal. They can sting your nose too on smelling them...
There haven't been any mention of it for over a year, and the viceprecident of alchem told me they have fixed it, but for over a year ago, there where rubbery notes in some of alchem's nic(nicselect).
There have also been the kerosene type issue with some nics, which I don't know about myself...
And as danny stated then the diluted down product shouldn't be smelling bad...
I would still try it though...
Btw, there have been previously reported issues with vg and pg, where they had a very plastic type smell to them, and when then they were left with lid off for an our or two, or maybe less, I can't remember precisely, then that note vent away and everything where fine again, so maybe you could try that, but other than that, and what I myself would do, is as stated, contact the vendor...
Edit: Also, when vg goes bad, because of heat usually(25C+ celsius), then it gets a slight sour'ishness in the smell, which is very noticeable when taking a spoon and tasting it, and also when vaping it. I've had to ditch 5L about in total by now because of that, as I don't have air condition where I live and at summer it's 30C celsius inside. It's just as sour as sweet and can be vaped, but just annoying...
With nic, then it just exaggerates the notes greatly when oxidized and can also make it harsher/more peppery at times, but I don't notice that myself now at 3mg, only once i've noticed that, but that was vg 12mg after over a year at room temp + summer time with 30C celsius and that was actually not even in dark closet, but sat on an open shelf half full in clear plastic, and I only used it for a day or so as an emergency, as I had to ditch my vg because it had gone bad, and I had to wait to get more delivered the next day(I think vg with nic can hold up better, or else it was because it was another brand, that it didn't get bad)...