diff --git a/src/field/field3d.cxx b/src/field/field3d.cxx
index 70569027c3..a124141634 100644
--- a/src/field/field3d.cxx
+++ b/src/field/field3d.cxx
@@ -544,7 +544,12 @@ void Field3D::applyParallelBoundary() {
   TRACE("Field3D::applyParallelBoundary()");
 
   checkData(*this);
-  ASSERT1(hasParallelSlices());
+  if (isFci()) {
+    ASSERT1(hasParallelSlices());
+  }
+  if (!hasParallelSlices()) {
+    return;
+  }
 
   // Apply boundary to this field
   for (const auto& bndry : getBoundaryOpPars()) {
@@ -557,7 +562,12 @@ void Field3D::applyParallelBoundary(BoutReal t) {
   TRACE("Field3D::applyParallelBoundary(t)");
 
   checkData(*this);
-  ASSERT1(hasParallelSlices());
+  if (isFci()) {
+    ASSERT1(hasParallelSlices());
+  }
+  if (!hasParallelSlices()) {
+    return;
+  }
 
   // Apply boundary to this field
   for (const auto& bndry : getBoundaryOpPars()) {
@@ -570,7 +580,12 @@ void Field3D::applyParallelBoundary(const std::string& condition) {
   TRACE("Field3D::applyParallelBoundary(condition)");
 
   checkData(*this);
-  ASSERT1(hasParallelSlices());
+  if (isFci()) {
+    ASSERT1(hasParallelSlices());
+  }
+  if (!hasParallelSlices()) {
+    return;
+  }
 
   /// Get the boundary factory (singleton)
   BoundaryFactory* bfact = BoundaryFactory::getInstance();
@@ -589,7 +604,12 @@ void Field3D::applyParallelBoundary(const std::string& region,
   TRACE("Field3D::applyParallelBoundary(region, condition)");
 
   checkData(*this);
-  ASSERT1(hasParallelSlices());
+  if (isFci()) {
+    ASSERT1(hasParallelSlices());
+  }
+  if (!hasParallelSlices()) {
+    return;
+  }
 
   /// Get the boundary factory (singleton)
   BoundaryFactory* bfact = BoundaryFactory::getInstance();
@@ -611,7 +631,12 @@ void Field3D::applyParallelBoundary(const std::string& region,
   TRACE("Field3D::applyParallelBoundary(region, condition, f)");
 
   checkData(*this);
-  ASSERT1(hasParallelSlices());
+  if (isFci()) {
+    ASSERT1(hasParallelSlices());
+  }
+  if (!hasParallelSlices()) {
+    return;
+  }
 
   /// Get the boundary factory (singleton)
   BoundaryFactory* bfact = BoundaryFactory::getInstance();