--- a/services/sync/modules/bookmark_validator.js
+++ b/services/sync/modules/bookmark_validator.js
@@ -249,16 +249,23 @@ class BookmarkValidator {
   }
 
   _followQueries(recordsByQueryId) {
     for (let entry of recordsByQueryId.values()) {
       if (entry.type !== "query" && (!entry.bmkUri || !entry.bmkUri.startsWith(QUERY_PROTOCOL))) {
         continue;
       }
       let params = new URLSearchParams(entry.bmkUri.slice(QUERY_PROTOCOL.length));
+      // Queries with `excludeQueries` won't form cycles because they'll
+      // exclude all queries, including themselves, from the result set.
+      let excludeQueries = params.get("excludeQueries");
+      if (excludeQueries === "1" || excludeQueries === "true") {
+        // `nsNavHistoryQuery::ParseQueryBooleanString` allows `1` and `true`.
+        continue;
+      }
       entry.concreteItems = [];
       let queryIds = params.getAll("folder");
       for (let queryId of queryIds) {
         let concreteItem = recordsByQueryId.get(queryId);
         if (concreteItem) {
           entry.concreteItems.push(concreteItem);
         }
       }

--- a/services/sync/tests/unit/test_bookmark_validator.js
+++ b/services/sync/tests/unit/test_bookmark_validator.js
@@ -337,16 +337,24 @@ add_task(async function test_cswc_client
   await PlacesUtils.bookmarks.insertTree({
     guid: PlacesUtils.bookmarks.menuGuid,
     children: [{
       // A query for the menu, referenced by its local ID instead of
       // `BOOKMARKS_MENU`. This should be reported as a cycle.
       guid: "dddddddddddd",
       url: `place:folder=${PlacesUtils.bookmarksMenuFolderId}`,
       title: "Bookmarks Menu",
+    }, {
+      // A query that references the menu, but excludes itself, so it can't
+      // form a cycle.
+      guid: "iiiiiiiiiiii",
+      url: `place:folder=BOOKMARKS_MENU&folder=UNFILED_BOOKMARKS&` +
+           `folder=TOOLBAR&queryType=1&sort=12&maxResults=10&` +
+           `excludeQueries=1`,
+      title: "Recently Bookmarked",
     }],
   });
 
   await PlacesUtils.bookmarks.insertTree({
     guid: PlacesUtils.bookmarks.toolbarGuid,
     children: [{
       guid: "eeeeeeeeeeee",
       type: PlacesUtils.bookmarks.TYPE_FOLDER,