Hmmmmm, well all that I can say at this point is that those error messages do not show up using exim on FREESCO as localhost, nor do they show up using my ISP's SMTP server. However in both cases I am using Thunderbird as my email client.
The date field is generated by the smtpclient binary using the 'timestamp()' function. So I am not sure why that would ever be an issue unless the original programmer got it wrong somehow. I see that specific function uses 'localtime(&now)'. So I am wondering if you have a timezone file added into your FREESCO box or if you are just using a standard +-xxxx time offset. Timezone files are in the 04x distribution and can be added to the /boot/tmz directory and a reboot is required to activate them.