When copying category properties, all the EditConst flags are not checked. This overrides variables that should not be written.

If you create two actors that have the same structure of variables in a category, and you try to copy the category variables of one actor into the other, variables that have ReadOnly/EditConst specifiers are also written.

This issue was first triggered by filling the variable values by a Factory, but you can reproduce it more easily the following way:

1- Create a C++ Actor with some variables, and you can also test it with a struct that of course has some variables inside. All these variables should be inside the same Category.
2- Mark all the variables with the UPROPERTY EditAnywhere,
3- Create 2 blueprint actors that derive from the C++ Actor class, and fill the variables with different values.
4- After changing the values, go back and change the UPROPERTY to VisibleAnywhere of all the variables.
5- Open Unreal again, open both actors, and in the variables category select "Copy All Properties in Category".
6- Go to the other Actor and select "Paste All Properties in Category". You should be able to paste all the properties althought the variables have the VisibleAnywhere/EditConst properties.