Drop the type for now, fixes https://github.com/orgs/firefly-iii/discussions/8750

app/Api/V1/Controllers/Models/Transaction/UpdateController.php

@@ -72,6 +72,11 @@ class UpdateController extends Controller
         app('log')->debug('Now in update routine for transaction group!');
         $data             = $request->getAll();
 
+        # Fixes 8750.
+        foreach($data['transactions'] as $index => $info) {
+            unset($data['transactions'][$index]['type']);
+        }
+
         $transactionGroup = $this->groupRepository->update($transactionGroup, $data);
         $manager          = $this->getManager();