diff --git a/app/Transformers/BillTransformer.php b/app/Transformers/BillTransformer.php
index a7aac08745..bb3ff233df 100644
--- a/app/Transformers/BillTransformer.php
+++ b/app/Transformers/BillTransformer.php
@@ -95,6 +95,7 @@ class BillTransformer extends TransformerAbstract
     public function transform(Bill $bill): array
     {
         $paidData = $this->paidData($bill);
+        $payDates = $this->payDates($bill);
         $data     = [
             'id'                  => (int)$bill->id,
             'name'                => $bill->name,
@@ -107,7 +108,7 @@ class BillTransformer extends TransformerAbstract
             'automatch'           => intval($bill->automatch) === 1,
             'active'              => intval($bill->active) === 1,
             'attachments_count'   => $bill->attachments()->count(),
-            'pay_dates'           => $this->payDates($bill),
+            'pay_dates'           => $payDates,
             'paid_dates'          => $paidData['paid_dates'],
             'next_expected_match' => $paidData['next_expected_match'],
             'links'               => [
@@ -217,6 +218,9 @@ class BillTransformer extends TransformerAbstract
      */
     protected function payDates(Bill $bill): array
     {
+        if (is_null($this->start) || is_null($this->end)) {
+            return [];
+        }
         $set          = new Collection;
         $currentStart = clone $this->start;
         while ($currentStart <= $this->end) {