If steeping actually means steeping as a DIY mixer understands it, then I think Danny has it. Sounds like it is slightly overflavored. Since too much flavoring can taste like too little flavoring and it seems to be a confusing notion to many new mixers, some horse's rearend that goes by the name Hoosier on ECF wrote a blog about flavoring levels so he wouldn't have to keep repeating the same thing over and over on posts. If you find Hoosier, kick him hard.
If your "steeping" is actually what a DIY mixer calls Airing-Out or letting a mix Breathe, then all bets are off. It could be too much flavoring has evaporated or the nicotine is too oxidized and is covering the flavor...hard to tell.
I'll bet when Danny asked for detail, he was hoping for manufacturer of the flavoring along with the flavoring name. There's a bunch out there and each one is completely different than the others. You can get flavorings with the same name and one may work a 1.5% and the other works better at 15% and they'll taste different from each other too.