Index: /branches/release-36/lib/MT/Author.pm
===================================================================
--- /branches/release-36/lib/MT/Author.pm (revision 2087)
+++ /branches/release-36/lib/MT/Author.pm (revision 2099)
@@ -363,14 +363,33 @@
             }
             ($perm, my $sys_perm) = @perm;
-            $perm->add_permission($sys_perm);
+            $perm->add_permissions($sys_perm);
         } elsif (@perm == 1) {
             $perm = $perm[0];
             if (!$perm->blog_id) {
                 $perm->blog_id($obj->id);
-                delete $perm->{column_values}->{id};
-                delete $perm->{changed_cols}->{id};
+                delete $perm->{column_values}{blog_id};
+                delete $perm->{changed_cols}{blog_id};
             }
-        } elsif (@perm) {
-            die "invalid permissions for author " . $author->id;
+        } elsif (@perm > 2) {
+            # Condition sometimes caused by saving preferences. BugId:79501
+            # Handle by merging permissions and removing all but one
+            # Not ideal, but better than dying...
+            my ($sys_perm) = grep { ! $_->blog_id } @perm;
+            my @blog_perms = grep { $_->blog_id } sort { $b->modified_on cmp $a->modified_on } @perm;
+
+            my $new_perm = shift @blog_perms; # take last one saved
+            if (@blog_perms) {
+                foreach my $more_perms (@blog_perms) {
+                    $new_perm->add_permissions($more_perms);
+                    $new_perm->add_restrictions($more_perms);
+                    $more_perms->remove;
+                }
+                # save merged permission record
+                $new_perm->save;
+            }
+            $new_perm->add_permissions($sys_perm);
+            $new_perm->add_restrictions($sys_perm);
+            $perm = $new_perm;
+            @perm = ($perm);
         }
     } else {
Index: /branches/release-36/lib/MT/Permission.pm
===================================================================
--- /branches/release-36/lib/MT/Permission.pm (revision 1823)
+++ /branches/release-36/lib/MT/Permission.pm (revision 2099)
@@ -138,4 +138,25 @@
     }
 
+    sub add_restrictions {
+        my $perms = shift;
+        my ($more_perm) = @_;
+        if ( my $more = $more_perm->restrictions ) {
+            if ( $more =~ /'administer_blog'/ ) {
+                $more = _all_perms('blog');
+            }
+            my $cur_perm = $perms->restrictions;
+            my @newperms;
+            for my $p ( split ',', $more ) {
+                $p =~ s/'(.+)'/$1/;
+                next if $perms->has($p);
+                push @newperms, $p;
+            }
+            return unless @newperms;
+            my $newperm = "'" . join( "','", @newperms ) . "'";
+            $newperm = "$cur_perm,$newperm" if $cur_perm;
+            $perms->restrictions($newperm);
+        }
+    }
+
     # Sets permissions of those in a particular set
     sub set_full_permissions {