If two characters are in different channels or instances, or in different “phases” where the visible NPCs depend on quest progress, they see different worlds.
Why The second character is assigned to a different channel, or its quest stage differs → Effect The server doesn’t send that NPC to that character (working as intended) → On screen The NPC is missing on one side only. It looks like a bug but is by design
Primary owner Game team (Server development) · Also Game team (Client development)
Game team action items
Server: send channel and phase info to the client, add “check both characters’ channel and quest stage” to the QA checklist. Client: show the channel and phase on screen.
On the graph
Outliers only · Nearby entity count per client, channel/phase
Where to look
The two characters’ channel numbers and progress on the relevant quest compared in the game, then checked again with both on the same channel and stage. With server entity send logs, why that NPC wasn’t sent to that character (channel, phase)
Confirmed if
The two characters differ in channel or quest stage, and the NPC shows up once they match
Ruled out if
Same channel and stage but the NPC is missing on one side only: points to spawn messages dropped during loading, spawn data lost in the burst after entering, or an AOI registration race
Check with
The player’s own environment
Learn more
Also check whether quest progress is saved per account or per character. With two characters on the same account, one character’s progress can change the other’s phase.
Sources
Actor Relevancy in Unreal EngineEpic Games The server replicates only relevant actors to each connection and doesn’t send irrelevant ones