The exclusive DLC for Trails of Cold Steel IV that is given to people who own Trails of Cold Steel III is missing with no offline-installer. There's no installer for this DLC on either the website or in Galaxy extras.

GOG support has confirmed this problem, but we have no idea when or if this will ever get fixed. People buy on GOG because of the offline-installers and having content missing is unacceptable. This is basically a 40-60 Dollar DLC from a new game that just came out in April 2021, and there's little to no urgency at all from GOG to fix this.

If you own both of these games I urge you to please contact support, and help get the offline installer for this DLC available again to GOG users.

Edit: Issue has now been fixed by GOG.

Any update on this?

Edit. Nevermind

I am having the same issue and now waiting for 2 weeks for a solution from GOG. How has the problem been fixed in your case?

It's still not fixed for me. Did they give you a code or something?
Guess I'll have to log a ticket for this too.

I had lost hope but now support has notified me that the Costume Bundle is available in my library.

So for me worked support-ticket+patience.

How long approximately did everyone have to wait after submitting his tickets for the situation to get remedied? I submitted a ticket Friday, and I am already tired of waiting. It seems patience is key, but I don't have any.

For me it took about a week If I remember correctly. Patience is the key. If you don't receive an answer this week than you could try replying to the support ticket and see what happens.