diff --git a/services/track-changes/app/coffee/DiffGenerator.coffee b/services/track-changes/app/coffee/DiffGenerator.coffee
index 996c936612..c8229b96dc 100644
--- a/services/track-changes/app/coffee/DiffGenerator.coffee
+++ b/services/track-changes/app/coffee/DiffGenerator.coffee
@@ -42,14 +42,17 @@ module.exports = DiffGenerator =
 		newDiff = []
 		for part in diff
 			lastPart = newDiff[newDiff.length - 1]
-			if lastPart? and lastPart.i? and part.i? and lastPart.meta.user_id == part.meta.user_id
-				lastPart.i += part.i
-				lastPart.meta.start_ts = Math.min(lastPart.meta.start_ts, part.meta.start_ts)
-				lastPart.meta.end_ts = Math.max(lastPart.meta.end_ts, part.meta.end_ts)
-			else if lastPart? and lastPart.d? and part.d? and lastPart.meta.user_id == part.meta.user_id
-				lastPart.d += part.d
-				lastPart.meta.start_ts = Math.min(lastPart.meta.start_ts, part.meta.start_ts)
-				lastPart.meta.end_ts = Math.max(lastPart.meta.end_ts, part.meta.end_ts)
+			if lastPart? and lastPart.meta?.user? and part.meta?.user?
+				if lastPart.i? and part.i? and lastPart.meta.user.id == part.meta.user.id
+					lastPart.i += part.i
+					lastPart.meta.start_ts = Math.min(lastPart.meta.start_ts, part.meta.start_ts)
+					lastPart.meta.end_ts = Math.max(lastPart.meta.end_ts, part.meta.end_ts)
+				else if lastPart.d? and part.d? and lastPart.meta.user.id == part.meta.user.id
+					lastPart.d += part.d
+					lastPart.meta.start_ts = Math.min(lastPart.meta.start_ts, part.meta.start_ts)
+					lastPart.meta.end_ts = Math.max(lastPart.meta.end_ts, part.meta.end_ts)
+				else
+					newDiff.push part
 			else
 				newDiff.push part
 		return newDiff
diff --git a/services/track-changes/test/unit/coffee/DiffGenerator/DiffGeneratorTests.coffee b/services/track-changes/test/unit/coffee/DiffGenerator/DiffGeneratorTests.coffee
index 43c86cfb5d..848086dc2e 100644
--- a/services/track-changes/test/unit/coffee/DiffGenerator/DiffGeneratorTests.coffee
+++ b/services/track-changes/test/unit/coffee/DiffGenerator/DiffGeneratorTests.coffee
@@ -91,18 +91,18 @@ describe "DiffGenerator", ->
 		describe "with adjacent inserts with the same user_id", ->
 			it "should create one update with combined meta data and min/max timestamps", ->
 				diff = @DiffGenerator.compressDiff([
-					{ i: "foo", meta: { start_ts: 10, end_ts: 20, user_id: @user_id }}
-					{ i: "bar", meta: { start_ts: 5,  end_ts: 15, user_id: @user_id }}
+					{ i: "foo", meta: { start_ts: 10, end_ts: 20, user: { id: @user_id } }}
+					{ i: "bar", meta: { start_ts: 5,  end_ts: 15, user: { id: @user_id } }}
 				])
 				expect(diff).to.deep.equal([
-					{ i: "foobar", meta: { start_ts: 5, end_ts: 20, user_id: @user_id }}
+					{ i: "foobar", meta: { start_ts: 5, end_ts: 20, user: { id: @user_id } }}
 				])
 
 		describe "with adjacent inserts with different user_ids", ->
 			it "should leave the inserts unchanged", ->
 				input = [
-					{ i: "foo", meta: { start_ts: 10, end_ts: 20, user_id: @user_id }}
-					{ i: "bar", meta: { start_ts: 5,  end_ts: 15, user_id: @user_id_2 }}
+					{ i: "foo", meta: { start_ts: 10, end_ts: 20, user: { id: @user_id } }}
+					{ i: "bar", meta: { start_ts: 5,  end_ts: 15, user: { id: @user_id_2 } }}
 				]
 				output = @DiffGenerator.compressDiff(input)
 				expect(output).to.deep.equal(input)
@@ -110,18 +110,18 @@ describe "DiffGenerator", ->
 		describe "with adjacent deletes with the same user_id", ->
 			it "should create one update with combined meta data and min/max timestamps", ->
 				diff = @DiffGenerator.compressDiff([
-					{ d: "foo", meta: { start_ts: 10, end_ts: 20, user_id: @user_id }}
-					{ d: "bar", meta: { start_ts: 5,  end_ts: 15, user_id: @user_id }}
+					{ d: "foo", meta: { start_ts: 10, end_ts: 20, user: { id: @user_id } }}
+					{ d: "bar", meta: { start_ts: 5,  end_ts: 15, user: { id: @user_id } }}
 				])
 				expect(diff).to.deep.equal([
-					{ d: "foobar", meta: { start_ts: 5, end_ts: 20, user_id: @user_id }}
+					{ d: "foobar", meta: { start_ts: 5, end_ts: 20, user: { id: @user_id } }}
 				])
 
 		describe "with adjacent deletes with different user_ids", ->
 			it "should leave the deletes unchanged", ->
 				input = [
-					{ d: "foo", meta: { start_ts: 10, end_ts: 20, user_id: @user_id }}
-					{ d: "bar", meta: { start_ts: 5,  end_ts: 15, user_id: @user_id_2 }}
+					{ d: "foo", meta: { start_ts: 10, end_ts: 20, user: { id: @user_id } }}
+					{ d: "bar", meta: { start_ts: 5,  end_ts: 15, user: { id: @user_id_2 } }}
 				]
 				output = @DiffGenerator.compressDiff(input)
 				expect(output).to.deep.equal(input)