[Bug Report] Robot visualization freeze when resume sim in IsaacSim5.1

[AngLi-00]

Describe the bug

When I'm using the Isaac Lab main branch together with Isaac Sim 5.1, if I pause and then resume the simulation during runtime, the robot visualization freezes (as shown in the video provided below). However, after switching to Isaac Sim 4.5, I no longer encounter this issue. Moreover, if I launch Isaac Sim independently and import a asset, this issue does not occur when pausing and then resuming the simulation.

What could be causing this?

2025-12-25.13-20-04.mov

Steps to reproduce

python scripts/demos/sensors/multi_mesh_raycaster.py --num_envs 16 --asset_type anymal_d

System Info

Describe the characteristic of your environment:

• Commit: main branch 9d17b52

• Isaac Sim Version: 5.1

• OS: Ubuntu 22.04

• GPU: RTX 4090 & L40

• CUDA: 12.8

• GPU Driver: 580.95.05

• [ x ] I have checked that there is no similar issue in the repo (required)

• [ x ] I have checked that the issue is not in running Isaac Sim itself and is related to the repo

[garylvov]

AFAIK pausing and unpausing is not compatible with Isaac lab. You likely disrupt some callbacks by doing this