Describe the bug
When players board a train on my server, I can see that they have boarded, but I cannot see them move, even though they can move. My friend doesn't see me moving on the train either. Basically each player sees the others but they are stuck in the same position even if they move.

Expected behavior
Since we want to shoot a cinematic, it would be nice if you could see the movements.

Screenshots
Unfortunately, I don't have any screenshots, but I think you can imagine what I'm talking about.

System Information
OS: Windows 10

System Memory: 16GB

Allocated Memory: 10GB

CPU: Ryzen 7 2700x 4,2 Ghz

GPU: MSI RTX 2070 Ventus OC 8GB

IR-Version: 1.7.3_1.12.2

Forge-Version: 1.12.2 - 14.23.5.2854

My Modlist (1.12.2)
-SecurityCraft v1.8.18.2
-ArchitectureCraft
-MrCrayfish's Furniture Mod 6.3.0
-ChiselsandBits 14.33
-Decocraft 2.6.3
-derfl007's Road Mod 1.5.2
-DynamicLights
-Fureniku's Roads 1.1.6
-Golden Airport Pack [Immersive Vehicles] 1.2.7
-Immersive Vehicles 18.2.0
-Immersive Engineering 0.12-98
-Immersive Railroading 1.7.3
-InventoryTweaks 1.63
-JEI 4.15.0.291
-OptiFine HD_U_F5
-PTRLib 1.0.4
-Thutcore 5.21.0
-Thutmoses Elevators mod
-TrackAPI 1.2
-Trafficcontrol 0.2.2
-UNU Civilian Pack 18.0.0-3.5.0
-UNU Parts Pack 18.0.0-3.5.0
-WorldEdit Forge 6.1.10
-Xaeros Minimap 20.12.1

latest.log
https://pastebin.com/jMcq2AHE