How to turn off night mode in Play books?

Question

Google

Hello!
Faced a terrible problem - I can not turn off the night mode in play books. It is impossible to read during the day, the eyes begin to hurt, in connection with this, daytime reading has long been abandoned. But now you need to learn difficult material, and half an hour before going to bed is not good.
What I've already done:
-Reinstalling the app
-Checking the settings of the global blue light filter (the one in the phone settings) - it's disabled and toggling it when the app is open doesn't change anything
-Checking the app settings. A white background is selected, night mode is disabled, switching also does not change
anything -Hard reset of the phone
-Swotting in support of Google and feedback on the Play Market. To no avail.
This is exactly the night mode and exactly in the application - if at the moment when the book is open, press the home button, before folding the page takes on a normal view without a filter. Galaxy s8 phone. It's terribly annoying, and I have no idea what to do. Or is it not a bug and is it like that for everyone?