diff --git a/internal/executor/sandbox/convert.go b/internal/executor/sandbox/convert.go
index 158160e..fd92458 100644
--- a/internal/executor/sandbox/convert.go
+++ b/internal/executor/sandbox/convert.go
@@ -56,7 +56,8 @@ func convertPBCopyIn(
 				if err != nil {
 					return nil
 				}
-				if !info.IsDir() {
+				_, exists := copyIn[relPath]
+				if !info.IsDir() && !exists {
 					copyIn[relPath] = stage.CmdFile{Src: &absPath}
 				}
 				return nil