LastDelimiter does not find the last space character

Question

I am using C++ Builder 10.2 Tokyo, and I have to find the position of the last space in a String variable which has a value like "XXX YYYYY TYUR KXYZ";

If I use the function LastDelimiter(const System::UnicodeString Delimiters, const System::UnicodeString S) it returns 0, but if I use the UnicodeString method::LastDelimiter( UnicodeString Delimiter ) method it returns the length of the variable.

Here is the code I am using:

void TMyClass::SetVerbo()
{
    int nPosCut = 0;

    if( !this->Message.IsEmpty() ) // Message is a UnicodeString (String)
    {
        nPosCut = this->Message.LastDelimiter(String(" ")) + 1 ;
    }
    if( nPosCut > 0 )
        this->Verbo = this->Message.SubString(nPosCut, this->Message.Length() -nPosCut ) ;
}

While debugging the method call it gives me the correct value (34) although the result at nPosCut is 42 (Message length), as written in the code, or 0 if I change String(" ") to L" ".

What am I doing wrong?