diff --git a/src/grid/DAMASK_grid.f90 b/src/grid/DAMASK_grid.f90
index ef863e017..edf26af19 100644
--- a/src/grid/DAMASK_grid.f90
+++ b/src/grid/DAMASK_grid.f90
@@ -300,7 +300,8 @@ program DAMASK_spectral
      if (newLoadCase%outputfrequency < 1)  errorID = 836                                            ! non-positive result frequency
      write(6,'(2x,a,i5)')  'output  frequency:  ', newLoadCase%outputfrequency
      if (newLoadCase%restartfrequency < 1)  errorID = 839                                           ! non-positive restart frequency
-     write(6,'(2x,a,i5)')  'restart frequency:  ', newLoadCase%restartfrequency
+     if (newLoadCase%restartfrequency < huge(0)) &
+       write(6,'(2x,a,i5)')  'restart frequency:  ', newLoadCase%restartfrequency
      if (errorID > 0) call IO_error(error_ID = errorID, ext_msg = loadcase_string)                  ! exit with error message
    endif reportAndCheck
    loadCases = [loadCases,newLoadCase]                                                              ! load case is ok, append it
diff --git a/src/plastic_dislotwin.f90 b/src/plastic_dislotwin.f90
index 82498b0bf..344fb6c26 100644
--- a/src/plastic_dislotwin.f90
+++ b/src/plastic_dislotwin.f90
@@ -1159,12 +1159,11 @@ pure subroutine kinetics_twin(Mp,T,dot_gamma_sl,instance,of,&
    isFCC: if (prm%fccTwinTransNucleation) then
      s1=prm%fcc_twinNucleationSlipPair(1,i)
      s2=prm%fcc_twinNucleationSlipPair(2,i)
-     if (tau(i) < dst%tau_r_tw(i,of)) then
+     if (tau(i) < dst%tau_r_tw(i,of)) then                                                          ! ToDo: correct?
        Ndot0=(abs(dot_gamma_sl(s1))*(stt%rho_mob(s2,of)+stt%rho_dip(s2,of))+&
               abs(dot_gamma_sl(s2))*(stt%rho_mob(s1,of)+stt%rho_dip(s1,of)))/&                      ! ToDo: MD: it would be more consistent to use shearrates from state
                (prm%L_tw*prm%b_sl(i))*&
-               (1.0_pReal-exp(-prm%V_cs/(kB*T)*&
-               (dst%tau_r_tw(i,of)-tau)))
+               (1.0_pReal-exp(-prm%V_cs/(kB*T)*(dst%tau_r_tw(i,of)-tau(i))))                        ! P_ncs
      else
        Ndot0=0.0_pReal
      end if
@@ -1224,12 +1223,11 @@ pure subroutine kinetics_trans(Mp,T,dot_gamma_sl,instance,of,&
    isFCC: if (prm%fccTwinTransNucleation) then
      s1=prm%fcc_twinNucleationSlipPair(1,i)
      s2=prm%fcc_twinNucleationSlipPair(2,i)
-     if (tau(i) < dst%tau_r_tr(i,of)) then
+     if (tau(i) < dst%tau_r_tr(i,of)) then                                                          ! ToDo: correct?
        Ndot0=(abs(dot_gamma_sl(s1))*(stt%rho_mob(s2,of)+stt%rho_dip(s2,of))+&
               abs(dot_gamma_sl(s2))*(stt%rho_mob(s1,of)+stt%rho_dip(s1,of)))/&                      ! ToDo: MD: it would be more consistent to use shearrates from state
                (prm%L_tr*prm%b_sl(i))*&
-               (1.0_pReal-exp(-prm%V_cs/(kB*T)*&
-               (dst%tau_r_tr(i,of)-tau)))
+               (1.0_pReal-exp(-prm%V_cs/(kB*T)*(dst%tau_r_tr(i,of)-tau(i))))                        ! P_ncs
      else
        Ndot0=0.0_pReal
      end if