diff --git a/e2e-tests/data/external-dataset.json b/e2e-tests/data/external-dataset.json
index b0b1bf49e8..2a4003cbb2 100644
--- a/e2e-tests/data/external-dataset.json
+++ b/e2e-tests/data/external-dataset.json
@@ -37,6 +37,9 @@
             "rate": -0.5
           }
         },
+        {
+          "duration": 40000000
+        },
         {
           "duration": 30000000,
           "dynamics": {
@@ -48,4 +51,4 @@
       "type": "real"
     }
   }
-}
\ No newline at end of file
+}
diff --git a/src/types/simulation.ts b/src/types/simulation.ts
index d559032bff..6f6b8b85e9 100644
--- a/src/types/simulation.ts
+++ b/src/types/simulation.ts
@@ -27,9 +27,18 @@ export type Profile = {
   };
 };
 
+// Dynamics for real profiles (linear interpolation)
+export type RealDynamics = {
+  initial: number;
+  rate: number;
+};
+
+// Dynamics can be: simple value (discrete), RealDynamics (real), or null/missing (gap)
+export type ProfileDynamics = RealDynamics | string | number | boolean | null;
+
 export type ProfileSegment = {
   dataset_id: number;
-  dynamics: any;
+  dynamics?: ProfileDynamics;
   is_gap: boolean;
   profile_id: number;
   start_offset: string;
diff --git a/src/utilities/resources.test.ts b/src/utilities/resources.test.ts
index 1b63d22590..6c1ad77ba9 100644
--- a/src/utilities/resources.test.ts
+++ b/src/utilities/resources.test.ts
@@ -110,4 +110,82 @@ describe('sampleProfiles', () => {
 
     expect(resources).toEqual(expectedResources);
   });
+
+  test('Emit a real profile segment with missing/null dynamics as a gap instead of crashing', () => {
+    const profiles: Profile[] = [
+      {
+        dataset_id: 1,
+        duration: '00:00:03',
+        id: 1,
+        name: '/real/with_gap',
+        profile_segments: [
+          {
+            dataset_id: 1,
+            dynamics: { initial: 10, rate: -0.5 },
+            is_gap: false,
+            profile_id: 1,
+            start_offset: '00:00:00',
+          },
+          // Segment missing dynamics (e.g. a `{ duration }`-only external dataset segment) — previously crashed.
+          { dataset_id: 1, dynamics: null, is_gap: false, profile_id: 1, start_offset: '00:00:01' },
+          { dataset_id: 1, dynamics: { initial: 5, rate: 0 }, is_gap: false, profile_id: 1, start_offset: '00:00:02' },
+        ],
+        type: {
+          schema: { items: { initial: { type: 'real' }, rate: { type: 'real' } }, type: 'struct' },
+          type: 'real',
+        },
+      },
+    ];
+
+    const resources = sampleProfiles(profiles, '2022-09-01T00:00:00+00:00');
+
+    expect(resources).toEqual([
+      {
+        name: '/real/with_gap',
+        schema: { items: { initial: { type: 'real' }, rate: { type: 'real' } }, type: 'struct' },
+        values: [
+          { is_gap: false, x: 1661990400000, y: 10 },
+          { is_gap: false, x: 1661990401000, y: 9.5 },
+          { is_gap: true, x: 1661990401000, y: null },
+          { is_gap: true, x: 1661990402000, y: null },
+          { is_gap: false, x: 1661990402000, y: 5 },
+          { is_gap: false, x: 1661990403000, y: 5 },
+        ],
+      },
+    ]);
+  });
+
+  test('Skip a real profile segment whose dynamics is missing initial/rate', () => {
+    const profiles: Profile[] = [
+      {
+        dataset_id: 1,
+        duration: '00:00:01',
+        id: 1,
+        name: '/real/malformed',
+        profile_segments: [
+          {
+            dataset_id: 1,
+            dynamics: {} as Profile['profile_segments'][number]['dynamics'],
+            is_gap: false,
+            profile_id: 1,
+            start_offset: '00:00:00',
+          },
+        ],
+        type: {
+          schema: { items: { initial: { type: 'real' }, rate: { type: 'real' } }, type: 'struct' },
+          type: 'real',
+        },
+      },
+    ];
+
+    const resources = sampleProfiles(profiles, '2022-09-01T00:00:00+00:00');
+
+    expect(resources).toEqual([
+      {
+        name: '/real/malformed',
+        schema: { items: { initial: { type: 'real' }, rate: { type: 'real' } }, type: 'struct' },
+        values: [],
+      },
+    ]);
+  });
 });
diff --git a/src/utilities/resources.ts b/src/utilities/resources.ts
index 103c3e23c8..d0f9f68a27 100644
--- a/src/utilities/resources.ts
+++ b/src/utilities/resources.ts
@@ -1,6 +1,20 @@
-import type { Profile, Resource, ResourceValue } from '../types/simulation';
+import type { Profile, RealDynamics, Resource, ResourceValue } from '../types/simulation';
 import { getIntervalInMs } from './time';
 
+/**
+ * Type guard to check if dynamics represents a real profile (linear interpolation).
+ */
+function isRealDynamics(dynamics: unknown): dynamics is RealDynamics {
+  return (
+    typeof dynamics === 'object' &&
+    dynamics !== null &&
+    'initial' in dynamics &&
+    'rate' in dynamics &&
+    typeof (dynamics as RealDynamics).initial === 'number' &&
+    typeof (dynamics as RealDynamics).rate === 'number'
+  );
+}
+
 /**
  * Samples a list of profiles at their change points. Converts the sampled profiles to Resources.
  */
@@ -30,29 +44,33 @@ export function sampleProfiles(
 
         const { dynamics, is_gap } = segment;
 
-        if (type === 'discrete') {
-          values.push({
-            is_gap,
-            x: start + segmentOffset,
-            y: dynamics,
-          });
-          values.push({
-            is_gap,
-            x: start + nextSegmentOffset,
-            y: dynamics,
-          });
-        } else if (type === 'real') {
-          values.push({
-            is_gap,
-            x: start + segmentOffset,
-            y: dynamics.initial,
-          });
-          values.push({
-            is_gap,
-            x: start + nextSegmentOffset,
-            y: dynamics.initial + dynamics.rate * ((nextSegmentOffset - segmentOffset) / 1000),
-          });
+        // Compute y values based on segment type
+        let startY: ResourceValue['y'];
+        let endY: ResourceValue['y'];
+        let segmentIsGap: boolean;
+
+        if (is_gap || dynamics == null) {
+          segmentIsGap = true;
+          startY = null;
+          endY = null;
+        } else if (type === 'real' && isRealDynamics(dynamics)) {
+          segmentIsGap = false;
+          startY = dynamics.initial;
+          endY = dynamics.initial + dynamics.rate * ((nextSegmentOffset - segmentOffset) / 1000);
+        } else if (type === 'discrete') {
+          // Discrete - dynamics is the value itself
+          segmentIsGap = false;
+          startY = dynamics as ResourceValue['y'];
+          endY = dynamics as ResourceValue['y'];
+        } else {
+          // Type is not supported
+          continue;
         }
+
+        values.push(
+          { is_gap: segmentIsGap, x: start + segmentOffset, y: startY },
+          { is_gap: segmentIsGap, x: start + nextSegmentOffset, y: endY },
+        );
       }
 
       resources.push({ name, schema, values });