fix minor

Signed-off-by: Nitish Bharambe <nitish.bharambe@alliander.com>

Author: nitbharambe

power_grid_model_c/power_grid_model/include/power_grid_model/optimizer/tap_position_optimizer.hpp

@@ -327,7 +327,7 @@ inline auto get_edge_weights(TransformerGraph const& graph) -> TrafoGraphEdgePro
         // side via the bidirectional edge (if it exists). For delta configuration ABC, the above
         // situations can happen.
         // The logic still holds in meshed grids, albeit operating a more complex graph.
-        if (!is_unreachable(edge_src_rank) && !is_unreachable(edge_tgt_rank)) {
+        if (!is_unreachable(edge_src_rank) || !is_unreachable(edge_tgt_rank)) {
             if (edge_src_rank != edge_tgt_rank - 1) {
                 throw AutomaticTapInputError("The control side of a transformer regulator should be relatively further "
                                              "away from the source than the tap side.\n");