That is because in android you are using the Graphical User Interface option 3 and in windows you are using the option 2
That is the way water looks in windows 10 edition and pocket edition, it is not a bug. However, if you are saying that they should change this that is consider a request and should be in feedback.minecraft.net
That is because in android you are using the Graphical User Interface option 3 and in windows you are using the option 2