Laravel Nova ExportAsCsv action produces strange chars when adding a TZ_CONVERT() query condition

Question

Using Nova's ExportAsCsv action, I added a query condition to convert the timezone to limit what is returned based on that date range based on an active filter in the resource:

ExportAsCsv::make('Export')
            ->withFields(function ($request) {
                return [
                    Boolean::make('Convert Timezone', 'convert_timezone')
                        ->help('This will convert to the timezone.'),
                ];
            })
            ->withQuery(function (Builder $query) use ($request) {
                $date_filter = collect(json_decode(base64_decode($request->filters)))->where(
                    function ($filter) use ($query) {
                        if (!is_object($filter)) {
                            return false;
                        }

                        return property_exists($filter, "App\Nova\Filters\CustomDateFilter");
                    }
                )->first()->{"App\Nova\Filters\CustomDateFilter"};

                // Convert to original timezone for the report before getting the records.
                if ($request->get('convert_timezone')) {
                    $from_tz = config('app.timezone');
                    $to_tz = 'GMT-7';

                    $query
                        ->select(['orders.*', 'accounts.source'])
                        ->join('accounts', 'orders.account_id', '=', 'accounts.id')
                        ->whereRaw(
                            "DATE(CONVERT_TZ(orders.created_at, '$from_tz', '$to_tz')) = '$date_filter'"
                        );
                }
            })

This causes Nova to output a CSV that only contains this: Ôªø

If I remove the whereRaw condition that converts the timezone on the query, then there is no issue and the CSV exports as expected.

If I convert the query to SQL and run it manually on the DB, then it returns records like I expect.

How do I fix this so that Nova outputs the CSV data properly?