[SUBSCRIPTION_EXPIRY_DATE] error?

I have used the following in the subscription Thank-you Email body (subscription active):

"your subscription has been marked as expired since [SUBSCRIPTION_EXPIRY_DATE],"

the email output is "marked as expired since 31/12/2030"

The correct date of expiry was 04/12/2017

[I'm manually subscribing selected users to a special plan to cope with recurring payment issues]

SUBSCRIPTION_EXPIRY_DATE directly pulls from the expiry_date column within the _cbsubs_subscriptions database table. This should then offset based off the timezone. Recommend verifying the expiry_date in the database.

[I'm manually subscribing selected users to a special plan to cope with recurring payment issues]

What recurring payment issues? Is this a bug in a payment gateway you're experiencing?

The problem has been caused by re-locating the website with a new database during the upgrade to joomla 3 some time ago; recurring payment subs created before the upgrade no longer send IPN's to the new database; I am trying to resolve the consequent problems; I realise that the cause of the issue I reported in this thread is that I am assigning affected users to a new plan and the activate email to inform them of the issue; this email reads the created date of the newly assigned plan - of course it does; I would need to be able to read the expired plan record; to get the expiry date of the old plan. I need to rethink the activate message; sorry for the trouble and thanks for the response.
Is there any way in which I could have avoided this whole problem when I first moved the site?

Moving databases shouldn't cause issues with IPNs. What causes issues with IPNs is changing domain name since the IPN is just calling a URL on your site so if the domain name changes it won't be able to correctly reach your site. Only way a database move could cause problems is if when you moved your tables you renumbered the id columns causing the basket ids to no longer be correct. There's no real fixing this at this point if you already manually activated subscriptions as the original basket is now deactivated. My recommendation for those cases is just let the subscription expire and have your users resubscribe.