diff --git a/src/index.js b/src/index.js
index b82a306..ede1a64 100644
--- a/src/index.js
+++ b/src/index.js
@@ -109,6 +109,7 @@ export default class CSSSplitWebpackPlugin {
       index: i,
     });
     return postcss([chunk(this.options)]).process(input.source, {
+      from: undefined,
       map: {
         prev: input.map,
       },