In this test bench, they are using a APawn with a custom replicated Movement Component rather than using a ACharacter and they are getting a different result that ends up in a permanent softlock of the client who suffers it. This issue not only happens on a netculling scenario, it happens as well when someone late joins your game, even if the character is always relevant.

They were able to replicate this issue in a scenario where every single pawn was relevant and without late joiners. This means that the issue might be related solely to the possession system. However, being able to replicate it consistently with culling spheres might help to debug the issue. A side note to this is that it is unclear which factors trigger this kind of behavior when everything is relevant.

This was reported and tested in 4.22.3 (CL-7053642). This was reproduced in 4.23 (CL-7647024) and Main 4.24 (CL-7668962)

Steps to Reproduce
  1. Download and open the attached project
  2. In the Play Settings check the box for Dedicated Server and set the number of Players to 2
  3. You will observe two white spheres around each player, these spheres represent the net cull area
  4. Isolate Client 1 and Client 2 so they are not relevant between each other (leave their culling areas)
  5. With Client 2 isolated possess a vehicle
  6. Once Client 2 is inside the vehicle, join with Client 1 the culling sphere of Client 2.
  7. Once Client 2 is net relevant for Client 1, leave the vehicle with 'E'.
  8. Possess the vehicle with Client 1

Results: Client 2 ends up in a permanent softlock state

Expected: Client 2 can move as normal

Have Comments or More Details?

There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-78229 in the post.

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Won't Fix
ComponentUE - Networking
Affects Versions4.
Target Fix4.24
CreatedAug 1, 2019
ResolvedAug 7, 2019
UpdatedAug 9, 2019