Why is Google Now Launcher using Samsung Theme Store Icons although the theme is uninstalled?

I have a Samsung Galaxy S6 Edge, Android 5.1.1. I installed Google Now Launcher then I installed a theme from Samsung theme store, which replaced the default icons. After removing the theme and the launcher, I came back to Google Now, and although the theme was removed, the same Icons remain, even with default theme. Tried countless reinstalls of Google now launcher, but still no results. Here is what I mean: