Bug-hunting_simple-calculator_problem when we buy App apply color to all Simple Application

Expected behavior

I hope when I click on Apply colors to all Simple
Apps I can find the app to unlock the function

Actual behavior

The reality after I open the app can not be found

how to reproduce

• download simple calculator app in f-droidHere

• Launch app

• press the menu button at the top right

• press the settings

• click Customize colors

• click Apply colors to all Simple Apps

• click Apply colors to all Simple Apps

• ckick PURCHASEthere you will find theproblem

• Device used: Xiaomi redmi 3 RAM 2.00 GB

• Operating System: Android version 5.1.1 LMY47V

• Application version: 3.2.0

• Github Here

Recording Of The Bug