diff --git a/packages/backend-core/src/cache/tests/docWritethrough.spec.ts b/packages/backend-core/src/cache/tests/docWritethrough.spec.ts
index ab0de53bee..16e47ce3c3 100644
--- a/packages/backend-core/src/cache/tests/docWritethrough.spec.ts
+++ b/packages/backend-core/src/cache/tests/docWritethrough.spec.ts
@@ -7,9 +7,17 @@ import _ from "lodash"
 
 env._set("MOCK_REDIS", null)
 
+const WRITE_RATE_MS = 500
+
 const initialTime = Date.now()
 
-const WRITE_RATE_MS = 500
+function resetTime() {
+  tk.travel(initialTime)
+}
+function travelForward(ms: number) {
+  const updatedTime = Date.now() + ms
+  tk.travel(updatedTime)
+}
 
 describe("docWritethrough", () => {
   const config = new DBTestConfiguration()
@@ -28,7 +36,7 @@ describe("docWritethrough", () => {
     }
 
     beforeEach(() => {
-      tk.freeze(initialTime)
+      resetTime()
       documentId = structures.db.id()
       docWritethrough = new DocWritethrough(db, documentId, WRITE_RATE_MS)
     })
@@ -37,7 +45,7 @@ describe("docWritethrough", () => {
       await config.doInTenant(async () => {
         await docWritethrough.patch(generatePatchObject(2))
         await docWritethrough.patch(generatePatchObject(2))
-        tk.travel(Date.now() + WRITE_RATE_MS - 1)
+        travelForward(WRITE_RATE_MS - 1)
         await docWritethrough.patch(generatePatchObject(2))
 
         expect(await db.docExists(documentId)).toBe(false)
@@ -51,7 +59,7 @@ describe("docWritethrough", () => {
         await docWritethrough.patch(patch1)
         await docWritethrough.patch(patch2)
 
-        tk.travel(Date.now() + WRITE_RATE_MS)
+        travelForward(WRITE_RATE_MS)
 
         const patch3 = generatePatchObject(3)
         await docWritethrough.patch(patch3)
@@ -62,23 +70,79 @@ describe("docWritethrough", () => {
           ...patch2,
           ...patch3,
           _rev: expect.stringMatching(/1-.+/),
-          createdAt: new Date(initialTime + 500).toISOString(),
-          updatedAt: new Date(initialTime + 500).toISOString(),
+          createdAt: new Date(initialTime + WRITE_RATE_MS).toISOString(),
+          updatedAt: new Date(initialTime + WRITE_RATE_MS).toISOString(),
         })
       })
     })
 
+    it("date audit fields are set correctly when persisting", async () => {
+      await config.doInTenant(async () => {
+        const patch1 = generatePatchObject(2)
+        const patch2 = generatePatchObject(2)
+        await docWritethrough.patch(patch1)
+        travelForward(WRITE_RATE_MS)
+        const date1 = new Date()
+        await docWritethrough.patch(patch2)
+
+        travelForward(WRITE_RATE_MS)
+        const date2 = new Date()
+
+        const patch3 = generatePatchObject(3)
+        await docWritethrough.patch(patch3)
+
+        expect(date1).not.toEqual(date2)
+        expect(await db.get(documentId)).toEqual(
+          expect.objectContaining({
+            createdAt: date1.toISOString(),
+            updatedAt: date2.toISOString(),
+          })
+        )
+      })
+    })
+
     it("patching will not persist even if timeout hits but next patch is not callec", async () => {
       await config.doInTenant(async () => {
-        const patch1 = generatePatchObject(2)
-        const patch2 = generatePatchObject(2)
-        await docWritethrough.patch(patch1)
-        await docWritethrough.patch(patch2)
+        await docWritethrough.patch(generatePatchObject(2))
+        await docWritethrough.patch(generatePatchObject(2))
 
-        tk.travel(Date.now() + WRITE_RATE_MS)
+        travelForward(WRITE_RATE_MS)
 
         expect(await db.docExists(documentId)).toBe(false)
       })
     })
+
+    it("concurrent patches will override keys", async () => {
+      await config.doInTenant(async () => {
+        const patch1 = generatePatchObject(2)
+        await docWritethrough.patch(patch1)
+        const time1 = travelForward(WRITE_RATE_MS)
+        const patch2 = generatePatchObject(1)
+        await docWritethrough.patch(patch2)
+
+        const keyToOverride = _.sample(Object.keys(patch1))!
+        expect(await db.get(documentId)).toEqual(
+          expect.objectContaining({
+            [keyToOverride]: patch1[keyToOverride],
+          })
+        )
+
+        travelForward(WRITE_RATE_MS)
+
+        const patch3 = {
+          ...generatePatchObject(3),
+          [keyToOverride]: generator.word(),
+        }
+        await docWritethrough.patch(patch3)
+
+        expect(await db.get(documentId)).toEqual(
+          expect.objectContaining({
+            ...patch1,
+            ...patch2,
+            ...patch3,
+          })
+        )
+      })
+    })
   })
 })