GDP is about products or services. If someone is paid for digging a hole, then that a finished, delivered service. Filling it the same. If you dig and fill a hole without anyone paying you for either, sure it won't affect GDP, but if someone pays you, that the net result is no change does not alter the fact that you have been paid to dig a hole and to fill a hole.

The method used to calculate the investment can affect whether the income produced increase the GDP or whether only the consumption generated by that increased income is counted, but in a real-world scenario either alternative will increase the GDP.

> But perhaps you are implying GDP is not correctly calculated?

That GDP doesn't accurately reflect productive, useful effort for this reason has been a core part of the criticism of GDP since it was first formulated.