Include files in root not found by files in a subdirectory after updating to 4.25

Suppose I have a file “RootClass” in [Project source root]/RootClass.h.

Then I have another file “Class1” in [Project source root]/Class1Directory/Class1.h

What I used to always do inside Class1 is to #include "RootClass.h"

However, after updating my project from 4.20 to 4.25 (haven’t touched the project for a while), now I get an error saying that "RootClass.h" cannot be found. When I change the include to #include "../RootClass.h" the source compiles normally without errors, but this seems to me only like a messy, temporary solution.

It seems that the compiler does not have a reference to the root folder anymore, but I don’t know why. I had to add bLegacyPublicIncludePaths = false; to the my Build.cs after updating, other than that the build config is default as when a new project is created.