Some of our servers were updated with latest Microsoft patches last night, about midnight. Everything went smoothly, no one noticed, until this morning when some templates failed to process. To make things worse, it affected the way optional elements are removed. An unknown number of optional elements were left on pages when they had to be removed.
We do not know how many orders are affected. They are still being affected, but we are working on a patch right now. It is expected to be fixed within next 4 hours.
Please, check all orders before sending them into production.
We will post instructions how to fix them after uploading the patch. Otherwise you can email firstname.lastname@example.org with a list of order IDs or URLs and we’ll fix them up for you.
Unfortunately, this type of error was not logged and only visual checks would pick it up. Hopefully users did pick it up if it happened to them.
Update: the problem appears to be fixed, but we are still monitoring. Let us know if your templates are misbehaving.