This ticket lacks a bit of information for me to do anything with. Sure, there are a few "duplicated entries", but those are in fact different servers which happen to have the same name.

Can you provide screenshots of the issue you are seeing. Please create a screenshot of both servers you consider duplicates, including the part on the right that shows the details of that server. With that info I can trace what you are actually seeing and what is going on :) Tnx!

For example, in the arctic-tycooners group of servers, many pairs of servers have the same name, but in each pair, one server has an invite code, while the other server has an IP address. In this example, both servers have the same full name: arctic-tycooners OpenTTD/OpenTTD#4 [Medium] [NARS] [FIRS] [1900-2100]

Invite code	IP address

They also run two different versions. This suggests to me that someone is actually running both. I will investigate, but this feels like "human error" :)

The server name reddit.com/r/OpenTTD 4 - Vanilla (Toyland) appears twice on the server list, with each server having a seperate IPv4 address and running a seperate game. This is likely because the pair likely consists of a main and secondary server.

Server 1	Server 2

When clicking "Refresh" on both servers, the 1985 entry goes "SERVER OFFLINE", while the 2030 entry remains online and updates accordingly, but returns to the previous date on the next "Search Internet".

Before we jump to conclusions, lets first gather facts ;)

So basically, for pre-12.0 servers that have more than one IP, you see 1 entry each. This has always been the case, so that on its own is not a bug/problem. 12.0 solves that (finally). The only thing I wonder about is why one is updated (server-info-wise) and the other is not. That is something I want to look into :)

Example for 1.11.2:

• 1 entry on website with 2 IP.
• 3 entries in game with 3 IP.

Example for 12.0:

• 1 entry on website with 1 invite code.
• 2 entries in game with 2 invite codes.

It's more likely bug of game controller than OpenTTD itself, since OpenTTD only displays what is sent in the GC listing packet.

I am quite sure that experienced community servers like BTpro and Arctic tycooners does not run servers with the same names. And displaying two entries for each IP type or invite code is at best confusing.

Little sidenote: I also find it pretty useless to send some 6000+ newgrf info in the GC listing packet, since there is usually around 700-800 unique NewGRFs online at any time. But then, it could make only maybe 300kB difference in packet size, so maybe it's not so big deal nowadays.

Observed behaviour:

• For 1.11 servers all IPs showed up as separate server. They should be de-duplicated on their session-key.
• The TG server got a new invite-code (how? that should never happen?). Normally not an issue, possibly related to their server-setup.
• When a 12 server gets a new invite-code, the old one remains listed on one of the two GC instances.
• Servers upgrading from 1.11 to 12 remain listed under both versions; possibly only on one of the two GC instances.

Did a rolling restart of the GC instances; resolved all issues. Which means the database was correct, just the reflection of it in the GC instances was not.

Moving ticket to GC repo.

Restarting it was unfortunately only temporary solution. There are already new duplicates.