Update: I got the server log message for when I got disconnected, if that helps with analyzing what happened.
2022-02-01T22:54:26 1851.572 WRN NET: LiteNetLib: SendData requested for unknown client EntityID=830, PltfmId='Steam_76561197984762346', CrossId='EOS_00022ad529a34e039673f5bd7d65c154', OwnerID='Steam_76561197984762346', PlayerName='Nikson'
2022-02-01T22:54:26 1851.576 INF NET: LiteNetLib: Client disconnect from: 71.140.147.174:52616 (Timeout)
2022-02-01T22:54:26 1851.576 INF [NET] PlayerDisconnected EntityID=830, PltfmId='Steam_76561197984762346', CrossId='EOS_00022ad529a34e039673f5bd7d65c154', OwnerID='Steam_76561197984762346', PlayerName='Nikson'
2022-02-01T22:54:26 1851.578 INF DynamicMusic: 830 successfully removed from Bloodmoon state cache
2022-02-01T22:54:26 1851.578 WRN Client disconnected from dy mesh: Id: 830 Total: 2
2022-02-01T22:54:26 1851.578 WRN Client disconnect complete for 830 Total: 1
2022-02-01T22:54:26 1851.578 INF Player disconnected: EntityID=830, PltfmId='Steam_76561197984762346', CrossId='EOS_00022ad529a34e039673f5bd7d65c154', OwnerID='Steam_76561197984762346', PlayerName='Nikson'
2022-02-01T22:54:27 1851.708 INF [EAC] FreeUser: EntityID=830, PltfmId='Steam_76561197984762346', CrossId='EOS_00022ad529a34e039673f5bd7d65c154', OwnerID='Steam_76561197984762346', PlayerName='Nikson'
2022-02-01T22:54:27 1851.709 INF [EAC] Log: [EAC Server] [Info] [22:54:27:110][Windows][EAC Server] [Info][UnregisterClient] Client: 0000000000000002 PlayerGUID: 76561197984762346
2022-02-01T22:54:27 1851.736 INF GMSG: Player 'Nikson' left the game