diff --git a/src/engine/runtime.js b/src/engine/runtime.js
index 831a40d5194..58bb350c161 100644
--- a/src/engine/runtime.js
+++ b/src/engine/runtime.js
@@ -1414,13 +1414,18 @@ class Runtime extends EventEmitter {
             if (!blockInfo.disableMonitor && context.inputList.length === 0) {
                 blockJSON.checkboxInFlyout = true;
             }
-        } else if (blockInfo.blockType === BlockType.LOOP || blockInfo.branchIconURI) {
+        } else if (
+            blockInfo.branchIconURI || (
+                blockInfo.blockType === BlockType.LOOP &&
+                !Object.prototype.hasOwnProperty.call(blockInfo, 'branchIconURI')
+            )
+        ) {
             // Add icon to the bottom right of a loop block
             blockJSON[`lastDummyAlign${outLineNum}`] = 'RIGHT';
             blockJSON[`message${outLineNum}`] = '%1';
             blockJSON[`args${outLineNum}`] = [{
                 type: 'field_image',
-                src: blockInfo.branchIconURI || 'media://repeat.svg',
+                src: blockInfo.branchIconURI ?? 'media://repeat.svg',
                 width: 24,
                 height: 24,
                 alt: '*', // TODO remove this since we don't use collapsed blocks in scratch
diff --git a/test/unit/tw_branch_icon_uri.js b/test/unit/tw_branch_icon_uri.js
index 0ad9316a824..f001039e85e 100644
--- a/test/unit/tw_branch_icon_uri.js
+++ b/test/unit/tw_branch_icon_uri.js
@@ -22,9 +22,15 @@ test('branchIconURI', t => {
                 },
                 {
                     blockType: BlockType.CONDITIONAL,
-                    opcode: 'block2',
+                    opcode: 'block3',
                     text: 'CONDITIONAL with custom icon',
                     branchIconURI: 'data:whatever2'
+                },
+                {
+                    blockType: BlockType.LOOP,
+                    opcode: 'block4',
+                    text: 'LOOP with no icon',
+                    branchIconURI: ''
                 }
             ]
         })
@@ -34,6 +40,7 @@ test('branchIconURI', t => {
     t.equal(blocks[0].args2[0].src, 'media://repeat.svg', 'default custom icon');
     t.equal(blocks[1].args2[0].src, 'data:whatever1', 'LOOP with custom icon');
     t.equal(blocks[2].args2[0].src, 'data:whatever2', 'CONDITIONAL with custom icon');
+    t.same(blocks[3].args2, null, 'LOOP with no icon');
 
     t.end();
 });