diff --git a/packages/ember-cli-code-coverage/lib/attach-middleware.js b/packages/ember-cli-code-coverage/lib/attach-middleware.js
index 421c56c5..35211b62 100644
--- a/packages/ember-cli-code-coverage/lib/attach-middleware.js
+++ b/packages/ember-cli-code-coverage/lib/attach-middleware.js
@@ -69,11 +69,16 @@ function adjustCoverageKey(
   modifyAssetLocation
 ) {
   let relativePath = path.relative(root, filepath);
+
   let embroiderTmpPathRegex = /embroider\/.{6}/gm;
 
   // we can determine if file is coming from embroider based on how the path looks
   if (embroiderTmpPathRegex.test(filepath)) {
     relativePath = normalizeRelativePath(root, filepath);
+  } else if (relativePath.startsWith('..')) {
+    // This lives in a directory outside of the current one, likely a monorepo.
+    // In this case we can assume that the original path is correct.
+    return filepath;
   }
 
   let namespace = relativePath.split(path.sep)[0];