[CS:GO] Unbanned players can't connect - "STEAM validation rejected"

[KirillMysnik]

1. Player gets banned

Dropped iPlayer from server: Kicked by Console : You've been banned by an admin
Admin Level 3 Noob has banned iPlayer

2. First connection attempt

RejectConnection: 192.168.1.2:27005 - You've been banned by an admin

3. Second connection attempt

S3: Duplicate client connection: UserID: 13 SteamID 110000103f0aa12
RejectConnection: 192.168.1.2:27005 - STEAM validation rejected

4. Player gets unbanned

Admin Level 3 Noob has lifted iPlayer's ban

5. Unbanned player still gets rejected on the third (and further) connetion attempts

S3: Duplicate client connection: UserID: 13 SteamID 110000103f0aa12
RejectConnection: 192.168.1.2:27005 - STEAM validation rejected

When we reject connection for a SteamID-banned player, CS:GO seems to start rejecting all further connections from that player after player's first connection attempt as a banned player.
Changing the map solves the issue.

[KirillMysnik]

Although the issue was not solved, e764cae completely moves it to ConnectFilter package