I was not able to replicate this with the same merchant actually, but the merchant does have a double of the item in its possession. Which of your characters tried this trade?

This bug has been fixed in v5.7.00.

I came accross this just now while playing, really irratating as i set up factory for DVD production only to find out i can't sell them anywhere and I have all the dlc.

This bug will be fixed in the next post-release beta patch v5.7.00.

David,

I already reported that in this thread of the subsidiary forum (it seems there are always multiple locations where to file bugs... a bug tracker might help).

DVD are available as semi-product on release version (thus it is not specific to post-release one) when merely the Subsidiary DLC is activated.
As I pointed out in the other thread, it seems this semi-product is part of the Subsidiary DLC while actually being useful in the Digital Age one.

Maybe a mix-up of some sorts?

I have also DVD in the Manufacturer'sGuide although quite hidden. Version 5.6.16 Release with Subsidiary DLC enabled and Dgital Age DLC disabled. No mods.

DVD is listed in Products (P) in class Semi Products. Bring up the Product Details for DVD and press F1 for Manufacturer's Guide. (It is made from Aluminium and Plastic.)

Maybe DVD should be hidden in Products and for R&D units when not using DA?

I don't see DVD in the semi products list on the manufacturer's guide with the post-release beta version 5.6.08. Are you using a mod?

Yes, DVDs are for Digital Age DLC.

I am playing the newest Post-Release-Beta and also have the Subsidiary DLC.

For some reason I have DVDs as researchable and producable Semi-Product.

Well, "just for fun" I set up a factory to produce DVDs, but it seems like they are useless.

Neither they can be sold in any store (I tried electronics, computer and department stores) ...
not surprisingly, considering that it is classified as a semi product (and AFAIK there are no stores for semi products)
nor can I use it for the production of final products.

My suspicion is, that it that it is supposed to be part of the Digital Age-DLC and therefore shouldn't be accessible to people with just the Vanilla game and the Subsidiary DLC