diff --git a/Bugzilla/Bug.pm b/Bugzilla/Bug.pm
index e2ca0e92e..3a9e805a2 100644
--- a/Bugzilla/Bug.pm
+++ b/Bugzilla/Bug.pm
@@ -480,6 +480,7 @@ sub update
     my $delta_ts = shift || $dbh->selectrow_array('SELECT LOCALTIMESTAMP(0)');
 
     # You can't set these fields by hand
+    $self->{deadline} =~ s/\s+.*$//so;
     $self->{delta_ts} = $delta_ts;
     delete $self->{votes};
     delete $self->{lastdiffed};
@@ -498,7 +499,8 @@ sub update
 
     if ($self->id)
     {
-        ($changes, $old_bug) = $self->SUPER::update(@_);
+        $old_bug->{deadline} =~ s/\s+.*$//so;
+        ($changes, $old_bug) = $self->SUPER::update(undef, $old_bug);
     }
     else
     {
diff --git a/Bugzilla/Object.pm b/Bugzilla/Object.pm
index 4b2d07690..11e4b44f3 100644
--- a/Bugzilla/Object.pm
+++ b/Bugzilla/Object.pm
@@ -334,6 +334,7 @@ sub set_all
 sub update
 {
     my $self = shift;
+    my (undef, $old_self) = @_;
 
     my $dbh      = Bugzilla->dbh;
     my $table    = $self->DB_TABLE;
@@ -342,7 +343,7 @@ sub update
     $dbh->bz_start_transaction();
 
     # Use a copy of old object
-    my $old_self = $self->new($self->id);
+    $old_self ||= $self->new($self->id);
 
     my $numeric = $self->NUMERIC_COLUMNS;
     my $date    = $self->DATE_COLUMNS;