Floral/Chemical notes do exist in some flavors, or can occur at higher percentages in some flavors. To eliminate those notes, don't wait to see if they dissipate, the chemical/floral note is an indication of an incomplete mix, not a lack of steeping. Here are some suggestions:
1. Reducing the percentage flavoring of the primary can often times eliminate the floral/chemical note, or

2. Add 2% strawberry, or 2% raspberry to the mix. At these low percentages, they will not be significant, if they can be tasted at all, and they will help "neutralize" the offending chemical/floral notes. Primary flavoring at 7%+ will overwhelm these fruits at 2%. Give it a shot.

3. Adding a good balance of creams, sweeteners and vanilla, even to tobaccos will not overwhelm the mix, if mixed at under 6% (each), and will supercharge and enhance the primaries. In so doing, they will also eliminate the chemical/floral notes in most cases. Many juices, including tobaccos, DO have creams and vanillas at low percentages. They round, smooth, and enhance the mix very effectively, and in small percentages are not significant, often not detectable. In most cases, the creams/vanillas/sweeteners will be the missing ingredient that we often cannot put our finger on.
Good luck!