CSTV clients disconnect with NETWORK_DISCONNECT_BADDELTATICK due to sv_deltaticks_enforce

[Peeetman]

For my setup, when connecting a game client to a delayed CSTV stream (running on port 27020), the client disconnects after a while with:

NETWORK_DISCONNECT_BADDELTATICK

The game console logs consistently show that the CSTV connection is closed by the server due to delta-tick issues. This happens even though the CSTV setup, delay configuration, and Docker server environment are correct.

Root Cause

Valve introduced a server command on 27 November 2024:

sv_deltaticks_enforce

The default value (2) enforces strict delta-tick ordering and will kick all clients, including CSTV viewers, when their acknowledgements are out of order. This results in the disconnection error above.

Immediate Fix

sv_deltaticks_enforce 0

Disable enforcement like this CS2_ADDITIONAL_ARGS=+sv_deltaticks_enforce 0 #36

This disables delta-tick enforcement. After applying this, CSTV remains connected reliably, even with delayed streams (tv_delay 7).

Notes

• The issue is not related to Docker, the CS2 image, or CSTV setup.
• To be frank, disabling this feature is not an ideal long-term solution, but it appears to be either an upstream issue or something specific to my (network) environment.