It's Fine.
Depending on what you've installed, duplicates may be reported between:
Some Toys mods, and some SLAL Animation Packs
Some Toys mods, and Sexlab or Zaz Animation Pack
This is normal and fine.
FNIS is not registering them twice, wasting space, or doing anything bad. Toys&Love is not registering them twice either. Nor is Sexlab.
Why the dups though? There are a few cases:
The Toys Starter LovePack has many of the same animations that are in Billyy's pack. The starter pack is a convenience for people starting out. You don't need both, but there is no harm in installing both.
Toys&Love & Toy Story install "minimum requirement" animations that are also found elsewhere. This is so Spontaneous Orgasm in Toys, and Quests in Toy Story don't break, when the other sources are not installed.
SLaVE installs animations also found in Sexlab. This is so it can work if you don't install Sexlab.
Dark Desires Club installs animations also found in Zaz Animation Pack. This is so it can work if you don't install ZAP
Section D in this FAQ has some related info ... Love Packs & SLAL Animation Packs