UE 5.8 added a staleness check to `USmoothWalkingMode::GenerateWalkMove` based on the
`DidGenerateMove` rollback-blackboard entry. This check permanently fails inside
`UMoverComponent::GetPredictedTrajectory` on any actor whose Mover simulation does not
tick — which is exactly the case for simulated proxies using the *Interpolated*
“Simulated Proxy Network LOD”, the setting recommended by the Mover plugin README.
As a result, the facing spring (`FSmoothWalkingState`) is re-initialized on every
prediction sample, the predicted future rotation collapses to near zero, and any
Motion Matching selection that relies on predicted turn angle (pivots, spins,
sharp-turn animations) never triggers on simulated proxies. Local players and the
server are unaffected.
This reproduces in the stock Game Animation Sample (5.8), which ships with the
Mover character, `SimulatedProxyNetworkLOD=Interpolated`, and
`bSyncInputsForSimProxy=true`.
Is this issue already known to the engine team, and is a fix planned for an upcoming release?
If it is intended behavior, what is the recommended way to get correct trajectory prediction on Interpolated simulated proxies?