World Model discrepancies between Clients and Server - Bombs freezing in Air

Summary: We have experienced world model discrepancies between clients and server in coop games. Pipe bombs get froozen for the server resp. other players while are being thrown correctly for the throwing player.

Game Version: A20.6

Platform: Steam

OS/Version: Windows

CPU Model: three different configurations (thus irrelevant for the outcome)

System Memory: three different configurations (thus irrelevant for the outcome)

GPU Model and VRAM: three different configurations (thus irrelevant for the outcome)

Screen Resolution: three different configurations (thus irrelevant for the outcome)

Video Settings: three different configurations (thus irrelevant for the outcome)

Game mode: MP host + client (on host as well as on clients)

Did you wipe old saves? Yes

Did you start a new game? Yes (at A20.4)

Did you validate your files? Yes

Are you using any mods? Yes

EAC off

Status: NEW

Bug Description:

In a coop series, during our horde nights, we use nearly exclusively pipe bombs as weapons. While in the beginning of the horde night everything works well, after some time (in our last instance after around 3 hours ingame) the game engine starts having discrepancies in the world model concerning our pipe bombs. SOME (not all) bombs start freezing mid air on contact with blocks. While freezing mid air, they are USUALLY (maybe with exceptions) NOT displayed as such for the throwing player, but for the other players. For the throwing player, they look as if they would fall as required by the physics model. On the server side and thus for the other players, they get modeled as freezing mid air. But not even that for ALL other players in the same way.

You can get an impression from the matter from the videos of our last horde night:
Tandemview: https://viewsync.net/watch?v=aHXeI_DzEIc&v=6MjAt7II8m4&mode=solo
(videos available after 2022-11-12 12:00 GMT; problematic scenes beginning at 1:18:10)

Detailed steps to reproduce the bug:

1) Build base like seen in the video

2) Start Horde night with multiple players (two sufficient)

3) Start throwing/igniting bombs
4) Repeat for about 10 times

Actual result: Bombs start freezing. State of bombs start to have discrepancies between different players.

Expected result: Bombs should keep falling as required by game physics. Bombs should be displayed consistently between different players. They should have the same state on the server side as on each and every client side. If a bomb sticks somewhere for one player, it should stick at the same place at the same time for all other players, too. Not that they should stick somewhere at all, that is. They should keep falling. Always.