diff --git a/ProcessLib/UncoupledProcessesTimeLoop.cpp b/ProcessLib/UncoupledProcessesTimeLoop.cpp
index 4c3dd6773162fd0de5c6180fe0b99c137359331e..9ece9ab2b24f5e6249147d191702c1e5febdc889 100644
--- a/ProcessLib/UncoupledProcessesTimeLoop.cpp
+++ b/ProcessLib/UncoupledProcessesTimeLoop.cpp
@@ -889,6 +889,9 @@ void UncoupledProcessesTimeLoop::outputSolutions(
             pcs.preTimestep(x, _start_time,
                             process_data->timestepper->getTimeStep().dt(),
                             process_id);
+            // Update secondary variables, which might be uninitialized, before
+            // output.
+            pcs.computeSecondaryVariable(_start_time, x);
         }
         if (is_staggered_coupling)
         {