diff --git a/src/IO.f90 b/src/IO.f90
index 3fbeb4300..d0fdb0255 100644
--- a/src/IO.f90
+++ b/src/IO.f90
@@ -504,8 +504,6 @@ subroutine IO_error(error_ID,el,ip,g,instance,ext_msg)
 ! errors related to the grid solver
     case (831)
       msg = 'mask consistency violated in grid load case'
-    case (832)
-      msg = 'ill-defined L (line partly defined) in grid load case'
     case (833)
       msg = 'non-positive ratio for geometric progression'
     case (834)
diff --git a/src/grid/DAMASK_grid.f90 b/src/grid/DAMASK_grid.f90
index 2d049f702..5bb476792 100644
--- a/src/grid/DAMASK_grid.f90
+++ b/src/grid/DAMASK_grid.f90
@@ -218,12 +218,6 @@ program DAMASK_grid
     reportAndCheck: if (worldrank == 0) then
       print'(/,a,i0)', ' load case: ', l
       print*, ' estimate_rate:', loadCases(l)%estimate_rate
-      if (loadCases(l)%deformation%myType == 'L') then
-        do j = 1, 3
-          if (any(loadCases(l)%deformation%mask(j,1:3) .eqv. .true.) .and. &
-              any(loadCases(l)%deformation%mask(j,1:3) .eqv. .false.)) errorID = 832                ! each row should be either fully or not at all defined
-        enddo
-      endif
       if (loadCases(l)%deformation%myType == 'F') then
         print*, ' F:'
       else
diff --git a/src/grid/grid_mech_FEM.f90 b/src/grid/grid_mech_FEM.f90
index 16a5c440e..9cccd2fc0 100644
--- a/src/grid/grid_mech_FEM.f90
+++ b/src/grid/grid_mech_FEM.f90
@@ -370,7 +370,7 @@ subroutine grid_mechanical_FEM_forward(cutBack,guess,Delta_t,Delta_t_old,t_remai
     ! calculate rate for aim
     if     (deformation_BC%myType=='L') then                                                        ! calculate F_aimDot from given L and current F
       F_aimDot = F_aimDot &
-               + merge(.0_pReal,matmul(deformation_BC%values, F_aim_lastInc),deformation_BC%mask)
+               + matmul(merge(.0_pReal,deformation_BC%values,deformation_BC%mask),F_aim_lastInc)
     elseif (deformation_BC%myType=='dot_F') then                                                    ! F_aimDot is prescribed
       F_aimDot = F_aimDot &
                + merge(.0_pReal,deformation_BC%values,deformation_BC%mask)
diff --git a/src/grid/grid_mech_spectral_basic.f90 b/src/grid/grid_mech_spectral_basic.f90
index ced767f5f..6f382d639 100644
--- a/src/grid/grid_mech_spectral_basic.f90
+++ b/src/grid/grid_mech_spectral_basic.f90
@@ -321,7 +321,7 @@ subroutine grid_mechanical_spectral_basic_forward(cutBack,guess,Delta_t,Delta_t_
     ! calculate rate for aim
     if     (deformation_BC%myType=='L') then                                                        ! calculate F_aimDot from given L and current F
       F_aimDot = F_aimDot &
-               + merge(.0_pReal,matmul(deformation_BC%values, F_aim_lastInc),deformation_BC%mask)
+               + matmul(merge(.0_pReal,deformation_BC%values,deformation_BC%mask),F_aim_lastInc)
     elseif (deformation_BC%myType=='dot_F') then                                                    ! F_aimDot is prescribed
       F_aimDot = F_aimDot &
                + merge(.0_pReal,deformation_BC%values,deformation_BC%mask)
diff --git a/src/grid/grid_mech_spectral_polarisation.f90 b/src/grid/grid_mech_spectral_polarisation.f90
index 3821cac4d..7a4ae7595 100644
--- a/src/grid/grid_mech_spectral_polarisation.f90
+++ b/src/grid/grid_mech_spectral_polarisation.f90
@@ -357,7 +357,7 @@ subroutine grid_mechanical_spectral_polarisation_forward(cutBack,guess,Delta_t,D
     ! calculate rate for aim
     if     (deformation_BC%myType=='L') then                                                        ! calculate F_aimDot from given L and current F
       F_aimDot = F_aimDot &
-               + merge(.0_pReal,matmul(deformation_BC%values, F_aim_lastInc),deformation_BC%mask)
+               + matmul(merge(.0_pReal,deformation_BC%values,deformation_BC%mask),F_aim_lastInc)
     elseif (deformation_BC%myType=='dot_F') then                                                    ! F_aimDot is prescribed
       F_aimDot = F_aimDot &
                + merge(.0_pReal,deformation_BC%values,deformation_BC%mask)