Is your symbol of type 'Annotate' and does it have a 'Term' property with no value?If so then try connecting the symbol to a net stub on the pin.
Its annotate type with term property i tried to connect to stub but the rectangle at the end of the line stay there after puting the NC syblol,
its seems that the symbol do not connects to the end of the line
Does it have a pin? The pin should be greater than 0 length to make connection easier.