On S6 (and a few other less common devices) shadows seem wrong. They are also apparently coming from the wrong direction compared to the position of the light and other devices rendering of then.
Most of the shadows are on static objects, but the light is set to real time shadows.
Shadows on everything sometimes.
Generally broken shadows and from the wrong direction.
Do you have a link to replicate an issue and test on actual device?
I have an S7 on which it is fine. That is a real S6 on Browserstack and it’s unlikely shadow issues are caused by the screen sending stuff.
Can you show a screenshot of troubling device of two links?