diff --git a/lib/conditionals.js b/lib/conditionals.js
index 315a803a..56a9a802 100644
--- a/lib/conditionals.js
+++ b/lib/conditionals.js
@@ -58,6 +58,10 @@
 
       return Promise.resolve(normalize.apply(this, arguments))
       .then(function(normalized) {
+        // let builder handle conditional interpolation when tracing
+        if (loader.builder)
+          return normalized;
+
         var conditionalMatch = normalized.match(conditionalRegEx);
         if (!conditionalMatch)
           return normalized;