General case description see Note
"Game Name", changes into

"Game Name: Expansion Edition"

Without actually including the Expansion.

So a simple warning, to double check before buying the game.

Note
I started a thread about this, but citing my specific case and speculative guesses as to why, combined with misunderstanding as to what I meant, sidetracked that thread and my intention to warn about the general case was lost.

If you want to see those specific cases, go to this clarification post in the original thread.
[url]https://www.gog.com/forum/general/new_publisher_underhand_sales_tactic_warning/post27[/url]

This is purely to warn that this can happen, use other thread for speculation and my case.
Keeping this on topic, this time (My bad post caused the side tracked thread.

So you tried to purchase the full/complete edition, but because of a bug you ended up buying only the base edition, without the expansion? In that case, presumably you were also charged for only the base edition, correct? So just buy the expansion separately, and you should be good. No, I think the reason was cheese.

Well, no evidence it was a bug, Support never denied it occurred.
Two occurrences of the same thing, on two different sites, within a few weeks, then both sites correct the page later.
It smells of a marketing decision, but it's not the sites I suspect.
My suspicion is the publisher, did this, each site missed it initially, then altered it when it was spotted.
No evidence for that either, but I'm cynical of publishers.

Europa Universalis 3: Complete Edition doesn't offer all of the DLC. It did at the time it was released, but since then more DLC came out. I wish Gog (and also Steam) would change the name.

Complaining about it the last time worked so well for him, maybe he's just trying to get another free upgrade DLC out of GOG.