Laravel returns "Incorrect datetime value" on update

For reasons unknown our Laravel 5.5 installation fails on all updates where the date starts with "2018-03-25".

Invalid datetime format: 1292 Incorrect datetime value: '2018-03-25 03:00:00' for column 'done_date' at row 1 (SQL: update `hours` set `done_date` = 2018-03-25 03:00:00, `updated_at` = 2018-05-31 12:19:36 where `id` = 481)

All other datetimes are fine.

Here's the table syntax:

CREATE TABLE hours ( id int(10) unsigned NOT NULL AUTO_INCREMENT, task_id int(11) DEFAULT NULL, project_id int(11) DEFAULT NULL, done_hours double(8,2) DEFAULT NULL, done_date timestamp NULL DEFAULT NULL, user_id int(11) DEFAULT NULL, info text COLLATE utf8mb4_unicode_ci, archived_at timestamp NULL DEFAULT NULL, created_at timestamp NULL DEFAULT NULL, updated_at timestamp NULL DEFAULT NULL, deleted_at timestamp NULL DEFAULT NULL, PRIMARY KEY (id) ) ENGINE=InnoDB AUTO_INCREMENT=906 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

What could cause this?

via Chebli Mohamed