diff --git a/org.lflang/src/org/lflang/generator/PortInstance.java b/org.lflang/src/org/lflang/generator/PortInstance.java
index 2841d3c854..303a9777b0 100644
--- a/org.lflang/src/org/lflang/generator/PortInstance.java
+++ b/org.lflang/src/org/lflang/generator/PortInstance.java
@@ -40,7 +40,7 @@ STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 
 /** 
  * Representation of a compile-time instance of a port.
- * Like {@link ReactorInstance}, one or more parents of this port
+ * Like {@link ReactorInstance}, if one or more parents of this port
  * is a bank of reactors, then there will be more than one runtime instance
  * corresponding to this compile-time instance.
  * 
diff --git a/org.lflang/src/org/lflang/generator/c/CTriggerObjectsGenerator.java b/org.lflang/src/org/lflang/generator/c/CTriggerObjectsGenerator.java
index d55bfb514d..a8f5af627d 100644
--- a/org.lflang/src/org/lflang/generator/c/CTriggerObjectsGenerator.java
+++ b/org.lflang/src/org/lflang/generator/c/CTriggerObjectsGenerator.java
@@ -781,7 +781,13 @@ private static String deferredFillTriggerTable(
                         }
                     }
                 }
-                cumulativePortWidth += port.getWidth();
+                // If the port is an input of a contained reactor, then we have to take
+                // into account the bank width of the contained reactor.
+                if (port.getParent() != reaction.getParent()) {
+                    cumulativePortWidth += port.getWidth() * port.getParent().getWidth();
+                } else {
+                    cumulativePortWidth += port.getWidth();
+                }
             }
             if (foundPort) code.endScopedBlock();
         }
diff --git a/test/C/src/multiport/DualBanks.lf b/test/C/src/multiport/DualBanks.lf
new file mode 100644
index 0000000000..8d5ec2727c
--- /dev/null
+++ b/test/C/src/multiport/DualBanks.lf
@@ -0,0 +1,41 @@
+target C;
+
+reactor Base(bank_index:int(0)) {
+    input I:int;
+    state received:bool(false);
+    
+    reaction(shutdown) {=
+        if(!self->received) {
+            lf_print_error_and_exit("Bank member %d received no input.",
+                self->bank_index
+            );
+        }
+    =}
+}
+
+reactor Hello extends Base {    
+    reaction(I) {=
+        printf("Hello %d\n", self->bank_index);
+        self->received = true;
+    =}
+}
+reactor World extends Base {
+    reaction(I) {=
+        printf("World %d\n", self->bank_index);
+        self->received = true;
+    =}
+}
+
+main reactor {
+    hellos = new[3] Hello()
+    worlds = new[3] World()
+
+    reaction(startup) -> hellos.I, worlds.I {=
+        for(int i = 0; i < hellos_width; i++) {
+            lf_set(hellos[i].I, true);
+        }
+        for(int i = 0; i < worlds_width; i++) {
+            lf_set(worlds[i].I, true);
+        }
+    =}
+}
diff --git a/test/C/src/multiport/DualBanksMultiport.lf b/test/C/src/multiport/DualBanksMultiport.lf
new file mode 100644
index 0000000000..b3300108f5
--- /dev/null
+++ b/test/C/src/multiport/DualBanksMultiport.lf
@@ -0,0 +1,47 @@
+target C;
+
+reactor Base(bank_index:int(0)) {
+    input[2] I:int;
+    state received:bool(false);
+    
+    reaction(shutdown) {=
+        if(!self->received) {
+            lf_print_error_and_exit("Bank member %d did not receive all inputs.",
+                self->bank_index
+            );
+        }
+    =}
+}
+
+reactor Hello extends Base {    
+    reaction(I) {=
+        if (I[0]->is_present && I[1]->is_present) {
+            printf("Hello %d\n", self->bank_index);
+            self->received = true;
+        }
+    =}
+}
+reactor World extends Base {
+    reaction(I) {=
+        if (I[0]->is_present && I[1]->is_present) {
+            printf("World %d\n", self->bank_index);
+            self->received = true;
+        }
+    =}
+}
+
+main reactor {
+    hellos = new[3] Hello()
+    worlds = new[3] World()
+
+    reaction(startup) -> hellos.I, worlds.I {=
+        for(int i = 0; i < hellos_width; i++) {
+            lf_set(hellos[i].I[0], true);
+            lf_set(hellos[i].I[1], true);
+        }
+        for(int i = 0; i < worlds_width; i++) {
+            lf_set(worlds[i].I[0], true);
+            lf_set(worlds[i].I[1], true);
+        }
+    =}
+}