Fix s_axis QBMM buffer reflection to branch on z_cc(l) < pi (#1357)

Author: sbryngelson

src/common/m_boundary_common.fpp

@@ -717,8 +717,13 @@ contains
             do i = 1, nb
                 do q = 1, nnode
                     do j = 1, buff_size
-                        pb_in(k, -j, l, q, i) = pb_in(k, j - 1, l - ((p + 1)/2), q, i)
-                        mv_in(k, -j, l, q, i) = mv_in(k, j - 1, l - ((p + 1)/2), q, i)
+                        if (z_cc(l) < pi) then
+                            pb_in(k, -j, l, q, i) = pb_in(k, j - 1, l + ((p + 1)/2), q, i)
+                            mv_in(k, -j, l, q, i) = mv_in(k, j - 1, l + ((p + 1)/2), q, i)
+                        else
+                            pb_in(k, -j, l, q, i) = pb_in(k, j - 1, l - ((p + 1)/2), q, i)
+                            mv_in(k, -j, l, q, i) = mv_in(k, j - 1, l - ((p + 1)/2), q, i)
+                        end if
                     end do
                 end do
             end do