any coughing along with that? you may have hit or passed through a vein or blood vessel. This might explain that taste. it would be the sovent like ba or other that you are tasting.
If your product is UG, I would say its the high BA content in the product. Always draw back for blood when you inject, if air comes into the syringe you are most likley in a muscle. If you draw back and blood comes into the syringe you are in the wrong place.
you hit blood on your injection w/o doubt. happens from time to time. pull out on the syringe next time after insertion to make sure you're in the muscle properly. some people get light headed or even pass out if they inject into the blood. i am a sick f--k and like the taste when it happens. but thats me.
actually, i just re-read your post and noticed that you tasted it ten minutes after inj. that is actually quite long if was directly into the bloodstream. maybe you were really close but not into it and that might explain the delay.