diff --git a/lib/gitWorkflow.js b/lib/gitWorkflow.js
index 2d2822dcd..56f3d2b0d 100644
--- a/lib/gitWorkflow.js
+++ b/lib/gitWorkflow.js
@@ -235,11 +235,12 @@ class GitWorkflow {
    */
   async applyModifications(ctx) {
     debug('Adding task modifications to index...')
-    await Promise.all(
-      // stagedFileChunks includes staged files that lint-staged originally detected.
-      // Add only these files so any 3rd-party edits to other files won't be included in the commit.
-      this.stagedFileChunks.map(stagedFiles => this.execGit(['add', '--', ...stagedFiles]))
-    )
+    // stagedFileChunks includes staged files that lint-staged originally detected.
+    // Add only these files so any 3rd-party edits to other files won't be included in the commit.
+    // This is run "serially" to prevent race conditions because `git add` is a locking operation.
+    for (const stagedFiles of this.stagedFileChunks) {
+      await this.execGit(['add', '--', ...stagedFiles])
+    }
     debug('Done adding task modifications to index!')
 
     const stagedFilesAfterAdd = await this.execGit(['diff', '--name-only', '--cached'])