Just a thought here ... I searched the OPs other threads / posts to try finding the recipe they used, and also googled how to get banana flavoring into the beer.
The most prevalent results were all people describing banana / bubblegum flavors in their beer as off flavors.
In looking at the OPs threads, it looks like his initial fermentation was a bit on the hot side ~78 degrees. I am wondering if the flavor he is getting is just this off flavor others have described as banana / bubblegum, or the intentional flavoring done during brewing or fermentation? In either case, this sounds really interesting, I would like to see the recipe as well!