diff --git a/src/trans_bounds.cpp b/src/trans_bounds.cpp
index e829c703ee..d5d2809e54 100644
--- a/src/trans_bounds.cpp
+++ b/src/trans_bounds.cpp
@@ -569,8 +569,8 @@ int proj_trans_bounds(PJ_CONTEXT *context, PJ *P, PJ_DIRECTION direction,
         // Sample points within the source grid
         for (int j = 1; j < side_pts - 1; ++j) {
             for (int i = 0; i < side_pts; ++i) {
-                x_boundary_array[i] = std::min(xmin, xmax) + i * delta_x;
-                y_boundary_array[i] = std::min(ymin, ymax) + j * delta_y;
+                x_boundary_array[i] = xmin + i * delta_x;
+                y_boundary_array[i] = ymin + j * delta_y;
             }
             proj_trans_generic(P, direction, x_boundary_array.data(),
                                sizeof(double), side_pts,
diff --git a/test/unit/test_c_api.cpp b/test/unit/test_c_api.cpp
index f7d7bf3964..443a896a0a 100644
--- a/test/unit/test_c_api.cpp
+++ b/test/unit/test_c_api.cpp
@@ -6223,8 +6223,8 @@ TEST_F(CApi, proj_trans_bounds_antimeridian_xy) {
                                     &out_right, &out_top, 21);
     EXPECT_TRUE(success == 1);
     EXPECT_NEAR(out_left, 1722483.900174921, 1);
-    EXPECT_NEAR(out_bottom, 4795714.1718160734, 1);
-    EXPECT_NEAR(out_right, 7095599.9757999768, 1);
+    EXPECT_NEAR(out_bottom, 5228058.6143420935, 1);
+    EXPECT_NEAR(out_right, 4624385.4948085546, 1);
     EXPECT_NEAR(out_top, 8692574.544944234, 1);
     double out_left_inv;
     double out_bottom_inv;
@@ -6255,10 +6255,10 @@ TEST_F(CApi, proj_trans_bounds_antimeridian) {
         proj_trans_bounds(m_ctxt, P, PJ_FWD, -55.95, 160.6, -25.88, -171.2,
                           &out_left, &out_bottom, &out_right, &out_top, 21);
     EXPECT_TRUE(success == 1);
-    EXPECT_NEAR(out_left, 4695514.1225397848, 1);
+    EXPECT_NEAR(out_left, 5228058.6143420935, 1);
     EXPECT_NEAR(out_bottom, 1722483.900174921, 1);
     EXPECT_NEAR(out_right, 8692574.544944234, 1);
-    EXPECT_NEAR(out_top, 7053083.9457852989, 1);
+    EXPECT_NEAR(out_top, 4624385.4948085546, 1);
     double out_left_inv;
     double out_bottom_inv;
     double out_right_inv;