diff --git a/src/utils/AttributionManager.js b/src/utils/AttributionManager.js
index f363d98f..869110ab 100644
--- a/src/utils/AttributionManager.js
+++ b/src/utils/AttributionManager.js
@@ -175,8 +175,20 @@ export class DiffAttributionManager {
     this._prevBOH = prevDoc.on('beforeObserverCalls', tr => {
       insertIntoIdSet(_prevDocInserts, tr.insertSet)
       insertIntoIdSet(prevDocDeletes, tr.deleteSet)
-      this.inserts = diffIdMap(this.inserts, tr.insertSet)
-      this.deletes = diffIdMap(this.deletes, tr.deleteSet)
+      if (tr.insertSet.clients.size < 2) {
+        tr.insertSet.forEach((idrange, client) => {
+          this.inserts.delete(client, idrange.clock, idrange.len)
+        })
+      } else {
+        this.inserts = diffIdMap(this.inserts, tr.insertSet)
+      }
+      if (tr.deleteSet.clients.size < 2) {
+        tr.deleteSet.forEach((attrRange, client) => {
+          this.deletes.delete(client, attrRange.clock, attrRange.len)
+        })
+      } else {
+        this.deletes = diffIdMap(this.deletes, tr.deleteSet)
+      }
       // @todo fire update ranges on `tr.insertSet` and `tr.deleteSet`
     })
     this._destroyHandler = nextDoc.on('destroy', this.destroy.bind(this))
diff --git a/src/utils/IdMap.js b/src/utils/IdMap.js
index 9b168717..f8c68492 100644
--- a/src/utils/IdMap.js
+++ b/src/utils/IdMap.js
@@ -321,6 +321,17 @@ export class IdMap {
     this.attrs = new Set()
   }
 
+  /**
+   * @param {(attrRange:AttrRange<Attrs>, client:number) => void} f
+   */
+  forEach (f) {
+    this.clients.forEach((ranges, client) => {
+      ranges.getIds().forEach((range) => {
+        f(range, client)
+      })
+    })
+  }
+
   /**
    * @param {ID} id
    * @return {boolean}
diff --git a/src/utils/IdSet.js b/src/utils/IdSet.js
index d9f06d81..5e236b73 100644
--- a/src/utils/IdSet.js
+++ b/src/utils/IdSet.js
@@ -113,6 +113,17 @@ export class IdSet {
     this.clients = new Map()
   }
 
+  /**
+   * @param {(idrange:IdRange, client:number) => void} f
+   */
+  forEach (f) {
+    this.clients.forEach((ranges, client) => {
+      ranges.getIds().forEach((range) => {
+        f(range, client)
+      })
+    })
+  }
+
   /**
    * @param {ID} id
    * @return {boolean}