Seo Url Changed Overnight

We received a complaint from one of our customers about the SEO addon. They claim there URL of some products changed without them updating the products.

They know this because they added working ULR’s in their newsletter and got feedback these links resulted in a 404 page not found.

Some examples of the changes:

URL before:

URL after:

Here there are two languages indicators added. Strange.

URL before:

URL after:

Here the language changed to German and NL is added. Very strange.

The webshop is running on v306 Professional. There are two languages active: Dutch and German. The SEO addon is configured to use “single url for all languages” and NOT “show language in URL”.

In the logging I can not find any indication these products were updated.

As you can imagine I have no clue what has caused the URL to change. I did read about some bug in previous v3 releases but this should be fixed in v306.

Any help or information is welcome and greatly appreciated.