Following the Arma Reforger 1.9 update out players began experiencing replication-related disconnects when joining our custom HQ Commander scenario.
The issue affected the M923A1 and Ural-4320 vehicle variants placed directly into the scenario using their original Arma Reforger prefabs, specifically the Transport and Engineer Filled variants.
Observed error
RplCreationError: Number of items mismatch.
expected=67, created=21
node='Assets/Vehicles/Wheeled/M923A1/M923A1_BASE.xob'
The client subsequently disconnects with:
REPLICATION / SYSTEM_FAILURE
group=1, reason=1
Steps taken
Removed the affected M923A1 and Ural-4320 variants from the custom scenario.
Confirmed that clients could connect without the replication disconnects.
Reintroduced the affected vehicles using freshly placed vanilla Arma Reforger prefabs.
Confirmed that the replication disconnects returned.
Created prefab overrides for the affected vehicle variants.
Confirmed that the scenario worked with the overridden prefabs.
Observed workaround
Creating overrides of the affected vehicle prefabs resolves the replication failures in this scenario.
Expected behaviour
Vehicle prefabs should be usable directly in custom scenarios without requiring a separate addon override solely for multiplayer replication to succeed.
Actual behaviour
Directly referenced vehicle prefabs trigger replication failures, while overriding the same vehicle variants allows players to connect successfully.
Additional information
The issue began following the Arma Reforger 1.9 update. It was reproduced across our main and test dedicated-server environments.
The precise underlying cause has not been established. It is unclear whether this behaviour represents an intended change to prefab handling or a regression introduced by the update.