--- a/misc.py
+++ b/misc.py
@@ -1005,25 +1005,26 @@ def generateDesktopMozharnessBuilders(na
         'repo_path': config['repo_path'],
         'script_repo_revision': config["mozharness_tag"],
     }
     dep_signing_servers = secrets.get(pf.get('dep_signing_servers'))
     nightly_signing_servers = secrets.get(pf.get('nightly_signing_servers'))
 
     # grab the l10n schedulers that nightlies will trigger (if any)
     triggered_nightly_schedulers = []
-    if (config['enable_l10n'] and platform in config['l10n_platforms'] and
-            '%s nightly' % pf['base_name'] in l10nNightlyBuilders):
-        triggered_nightly_schedulers = [
-            l10nNightlyBuilders['%s nightly' % pf['base_name']]['l10n_builder']
-        ]
-    elif is_l10n_with_mh(config, platform):
+    if is_l10n_with_mh(config, platform):
         scheduler_name = mh_l10n_scheduler_name(config, platform)
         triggered_nightly_schedulers.append(scheduler_name)
-
+    elif (config['enable_l10n'] and platform in config['l10n_platforms'] and
+            '%s nightly' % pf['base_name'] in l10nNightlyBuilders):
+        base_name = '%s nightly' % pf['base_name']
+        # see bug 1150015
+        l10n_builder = l10nNightlyBuilders[base_name]['l10n_builder']
+        assert(isinstance(l10n_builder, str))
+        triggered_nightly_schedulers.append(l10n_builder)
     # if we do a generic dep build
     if pf.get('enable_dep', True) or pf.get('enable_periodic', False):
         factory = makeMHFactory(config, pf, mh_cfg=mh_cfg,
                                 extra_args=base_extra_args,
                                 signingServers=dep_signing_servers,
                                 use_credentials_file=True,
                                 log_eval_func=return_codes_func)
         generic_builder = {
@@ -3370,17 +3371,16 @@ def mh_l10n_builddir_from_builder_name(b
     # replaces / with _
     return b_dir.replace('/', '_')
 
 
 def mh_l10n_scheduler_name(config, platform):
     pf = config['platforms'][platform]
     return '%s nightly l10n' % (pf['base_name'])
 
-
 def mh_l10n_builder_names(config, platform, branch, is_nightly):
     # let's check if we need to create builders for this config/platform
     names = []
     pf = config['platforms'][platform]
     product_name = pf['product_name']
     name = '%s %s %s' % (product_name, branch, platform)
     name = name.capitalize()
     if is_nightly: