Game Lag White Paper › Problems only some players hit

Client version or data mismatch Client version / data table mismatch

Cause ID pt-version · Primary owner Game team (Client development) · Also Game team (Server development)

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If the second client is a different install or isn’t fully patched, it doesn’t recognize new NPC IDs the server sends and silently ignores them.

Why An install in a different folder, or a client launched mid-patch → Effect Unknown NPC IDs or model IDs are skipped → On screen Only newly added NPCs are invisible on one side

Symptoms

Invisible / ghost entities

Factors

Packet loss

Who’s affected

One client on the same PC

When

Right after login or maintenance

Owner

Primary owner Game team (Client development) · Also Game team (Server development)

Game team action items

Client: send the data version on connect, when an unknown ID arrives log it and show a placeholder. Server: check the data version on connect and, if it differs, refuse the connection and prompt a patch.

On the graph

Outliers only · Unknown IDs received per client version

Where to look

The two clients’ executable paths and the client and data versions shown on screen or in logs. On the game side, the data version sent on connect and how many times unknown NPC or model IDs were received and skipped, logged

Confirmed if

The two clients differ in version or install folder, the invisible NPCs were added in a recent patch, and they show up in the fully patched install

Ruled out if

Same version and install folder but missing on one side only: points to a channel/phase difference or a loading or delivery cause

Check with

The player’s own environment

Sources

1. NetworkConfig class (Netcode for GameObjects 2.5) Unity
   Clients with different ProtocolVersion values don’t communicate, and ForceSamePrefabs checks for prefab list differences on connect

See also

Same layer: Problems only some players hit

• A lagging player moves in bursts on others’ screens
• Fast-forward on servers that process on arrival
• Per-player input buffer size
• Validation false positives concentrated on one ISP
• One lagging party member and boss mechanics
• A lagging client controls the monster
• Bloated data on one character
• Different channel, instance, or phase
• Spawn messages dropped during loading
• AOI registration race
• Lost baseline snapshot
• Missed despawn message (ghost entity)
• Spawn data lost in the burst after entering
• Entity ID reuse mix-up
• Fixed UDP port collision
• Sessions keyed by IP or device (bug)
• Multi-client restriction
• Background window throttling
• Simultaneous access to cache or asset files
• Streaming failure from memory or VRAM shortage
• Different display settings
• Per-connection send budget and priority
• Entities held back by clock estimate error

Same symptom (Invisible / ghost entities), other layers

• Slow storage delays asset streaming L1 Client game process
• Keepalive default of 2 hours L8 Sockets and protocols
• Slow start after idle L8 Sockets and protocols

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