Laravel Model->get returns 502 Bad Gateway

I am running Laravel 5.x with valet on OS X...

When I execute the following query, I get the response I am looking for...

$orders = \App\Order::with([
    'Customer' => function ($query) use ($filterFirst, $filterLast)
    {
        if($filterFirst) {
            $query->where('customers.first', 'LIKE', "{$filterFirst}%");
        }
        if($filterLast) {
            $query->where('customers.last', 'LIKE', "{$filterLast}%");
        }
        return $query;
    }
]);

However, When I execute this next query, I get a 502 Bad Gateway...

$orders = \App\Order::with([
    'Customer' => function ($query) use ($filterFirst, $filterLast)
    {
        if($filterFirst) {
            $query->where('customers.first', 'LIKE', "{$filterFirst}%");
        }
        if($filterLast) {
            $query->where('customers.last', 'LIKE', "{$filterLast}%");
        }
        return $query;
    },
    'Group' => function ($query) use ($filtercategory)
    {
        if($filtercategory) {
            $query->where('order_groups.groupid', '=', $filtercategory);
        }
        return $query;
    }
]);

Any ideas on how I can further troubleshoot this issue or why it may be happening?

via Chebli Mohamed