In OpenMesh, once a named property is added to an element, it will be permanent in the sense that the property survives the scope of the property manager as explained here.
My question is:

1.
Now I was adding a PROPERTY by property manager.

auto GroupMark = FProp<bool>(*this, "shellGroupMark");

Will GroupMark be initialized?

2.
When someFuncA() ends, the GroupMark is removed from the mesh.
Why can’t I use GroupMark inside someFuncB()?

void someFuncA()
{
    auto GroupMark = FProp<bool>(*this, "shellGroupMark");
  
    for (const SmartFaceHandle& face : faces())
    {
        if (!shellGroupMark[face])
        {
            if(someFuncB(face))
            {
                Some action;
            }
        }
    }
}

bool someFuncB(const SmartFaceHandle& startFace)
{
    //GroupMark cannot be used without undoing the annotation.
    //someFuncA() is not finished, why can't GroupMark be used?
    //auto GroupMark = FProp<bool>(*this, "shellGroupMark");
  
    for(const SmartFaceHandle& face : faces())
    {
　　　　shellGroupMark[face] = true;
    }
}

It would be greatly appreciated if you could explain the details.
Thanks.