The position operator in a Bloch representation acquires a gauge correction in the momentum space on top of the canonical position, which is called the anomalous position. We show that the anomalous position is generally orbital dependent and thus plays a crucial role in the description of the intrinsic orbital Hall effect in terms of Wannier basis. We demonstrate this from the first-principles calculation of orbital Hall conductivities of transition metals by Wannier interpolation. Our results show that consistent treatment of the velocity operator by including the correction term originating from the anomalous position predicts the orbital Hall conductivities different from those obtained by considering only the group velocity. We find the difference is crucial in several metals. For example, we predict negative signs of the orbital Hall conductivities for elements in groups X and XI such as Cu, Ag, Au, and Pd, for which the previous studies predicted positive signs. In this paper, we suggest the importance of consistently describing the spatial dependence of basis functions by first-principles methods, as it is fundamentally missing in the tight-binding approximation.