diff --git a/lib/spack/spack/audit.py b/lib/spack/spack/audit.py
index 3154723e162..faef15393d9 100644
--- a/lib/spack/spack/audit.py
+++ b/lib/spack/spack/audit.py
@@ -791,7 +791,7 @@ def check_virtual_with_variants(spec, msg):
                         return
                     error = error_cls(
                         f"{pkg_name}: {msg}",
-                        f"remove variants from '{spec}' in depends_on directive in {filename}",
+                        [f"remove variants from '{spec}' in depends_on directive in {filename}"],
                     )
                     errors.append(error)