diff --git a/lib/spack/spack/util/environment.py b/lib/spack/spack/util/environment.py
index c7ea4d67f40..1666f4711e3 100644
--- a/lib/spack/spack/util/environment.py
+++ b/lib/spack/spack/util/environment.py
@@ -542,6 +542,7 @@ def return_separator_if_any(*args):
                     search = sep.join(after_list[start:end + 1])
                 except IndexError:
                     env.prepend_path(x, after)
+                    continue
 
                 if search not in before:
                     # We just need to set the variable to the new value