adding a whereBetween clause doesnt return expected result set

I am using Laravel 5.6 and SQLite I am trying to return certain results between a time frame. The problem is that when I add a whereBetween clause on the created_at column it is missing results. created_at is of type DateTime

This query should return two results. I am grouping by c_sub_category and there are only two c_sub_categories but currently it is returning just 1 result

$data  = Tickets
            ::whereBetween('created_at', [$week["startDate"], $week["endDate"]])
            ->where('status', 'closed')
            ->where('category', '!=', 'New Development')
            ->groupBy('c_sub_category')
            ->get();

This query without the whereBetween clause returning two results which is correct

$data  = Tickets
            ->where('status', 'closed')
            ->where('category', '!=', 'New Development')
            ->groupBy('c_sub_category')
            ->get();

Other ways I have tried that also don't return the correct result set

$data  = Tickets
            ::where(function ($query) use ($week) {
                $query->whereBetween('created_at', [$week["startDate"], $week["endDate"]]);
            })
            ->where('category', '!=', 'New Development')
            ->where('status', 'closed')
            ->groupBy('c_sub_category')
            ->get();

$data  = Tickets
            ::where(function ($query) use ($week) {
                $query->whereBetween('created_at', [$week["startDate"], $week["endDate"]]);
            })
            ->where(function ($query) use ($week) {
                $query->where('category', '!=', 'New Development');
                      ->where('status', 'closed');

            })
            ->groupBy('c_sub_category')
            ->get();

via Chebli Mohamed