diff --git a/pkgs/development/libraries/vapoursynth/plugin-interface.nix b/pkgs/development/libraries/vapoursynth/plugin-interface.nix
index 55b2b03c893..95df3c97747 100644
--- a/pkgs/development/libraries/vapoursynth/plugin-interface.nix
+++ b/pkgs/development/libraries/vapoursynth/plugin-interface.nix
@@ -8,10 +8,11 @@ plugins: let
 
   getRecursivePropagatedBuildInputs = pkgs: lib.flatten
     (map
-      (pkg: pkg.propagatedBuildInputs ++ (getRecursivePropagatedBuildInputs pkg.propagatedBuildInputs))
+      (pkg: let cleanPropagatedBuildInputs = lib.filter lib.isDerivation pkg.propagatedBuildInputs;
+        in cleanPropagatedBuildInputs ++ (getRecursivePropagatedBuildInputs cleanPropagatedBuildInputs))
       pkgs);
 
-  deepPlugins = plugins ++ (getRecursivePropagatedBuildInputs plugins);
+  deepPlugins = lib.unique (plugins ++ (getRecursivePropagatedBuildInputs plugins));
 
   pluginsEnv = buildEnv {
     name = "vapoursynth-plugins-env";