Cron periodic daily mail: illegal option -- E

[kingfisher77]

Hi, recently we discovered the cron integration with Opnsense and tried all options. We found our solution and our cron jobs works fine. There is one thing which we could not fix which is possibly related to some of our tests.

Every night the cron job for "periodic daily" stops with complains about mail:

From root@fw  Sun Jun 21 03:01:39 2020
Return-Path: <root@fw>
X-Original-To: root
Delivered-To: root@fw
Received: by fw (Postfix, from userid 0)
        id 224C5D9FB03; Sun, 21 Jun 2020 03:01:39 +0200 (CEST)
From: Cron Daemon <root@fw>
To: root@fw
Subject: Cron <root@fw> periodic daily
X-Cron-Env: <SHELL=/bin/sh>
X-Cron-Env: <PATH=/etc:/bin:/sbin:/usr/bin:/usr/sbin>
X-Cron-Env: <HOME=/root>
X-Cron-Env: <LOGNAME=root>
X-Cron-Env: <USER=root>
Message-Id: <20200621010139.224C5D9FB03@fw>
Date: Sun, 21 Jun 2020 03:01:00 +0200 (CEST)
Status: RO

mail: illegal option -- E
Usage: mail [-iInv] [-s subject] [-c cc-addr] [-b bcc-addr] to-addr ...
            [- sendmail-options ...]
       mail [-iInNv] -f [name]
       mail [-iInNv] [-u user]

We cannot find the source for that. Could someone enlighten me?

Tobias