#16063 Severe latency (10+ seconds) rendering ANSI-colored `systemctl status` output over SSH, disappears with SYSTEMD_COLORS=0

Pre-submit Checks

I have searched Warp SSH issues and there are no duplicates
I have searched Warp known issues page and my issue is not there
I have technical issue and have included the logs (helps expedite the bug fix). Log instructions

Include shell output

time sudo systemctl status jellyfin
● jellyfin.service - Jellyfin Media Server
     Loaded: loaded (/usr/lib/systemd/system/jellyfin.service; enabled; preset: enabled)
    Drop-In: /etc/systemd/system/jellyfin.service.d
             └─jellyfin.service.conf, override.conf
     Active: active (running) since Sun 2026-09-13 20:55:52 CST; 4 days ago
 Invocation: f74600aa1e2e4b738a47641568fbddf5
   Main PID: 74365 (jellyfin)
      Tasks: 18 (limit: 14893)
     Memory: 459M (peak: 3.5G, swap: 37.2M, swap peak: 38.3M)
        CPU: 5min 24.506s
     CGroup: /system.slice/jellyfin.service
             └─74365 /usr/bin/jellyfin --webdir=/usr/share/jellyfin/web --ffmpeg=/usr/lib/jellyfin-ffmpeg/ffmpeg

Sep 17 20:59:59 homeserver jellyfin[74365]: [20:59:59] [INF] TasksRefreshChannels Completed after 0 minute(s) and 0 seconds
Sep 17 21:00:02 homeserver jellyfin[74365]: [21:00:02] [INF] Refreshing guide with 7 days of guide data
Sep 17 21:00:02 homeserver jellyfin[74365]: [21:00:02] [INF] Refresh Guide Completed after 0 minute(s) and 3 seconds
Sep 17 21:12:10 homeserver jellyfin[74365]: [21:12:10] [INF] Optimizing and vacuuming jellyfin.db...
Sep 17 21:12:11 homeserver jellyfin[74365]: [21:12:11] [INF] jellyfin.db optimized successfully!

real	0m11.791s
user	0m0.010s
sys	0m0.017s

Screenshots, videos, and logs

Describe the issue

When running commands that produce ANSI-colored, multi-line output with box-drawing Unicode characters (e.g. systemctl status) over an SSH session, Warp takes ~13 seconds to display the output. The exact same command with colors/pager disabled returns almost instantly. This does not happen in other terminals (native Terminal, same SSH connection, same server).

To Reproduce

SSH into a Linux server from Warp (via ssh user@host)
Run: time sudo systemctl status <any-running-service>
Observe the command takes ~13 seconds wall-clock time, even though the service status output is only ~10 lines.
Run the same command with colors disabled: time sudo SYSTEMD_COLORS=0 systemctl status <any-running-service> --no-pager
Observe this returns in well under 1 second.

Expected behavior

Output should render at roughly the same speed regardless of whether ANSI colors / Unicode box-drawing characters are present, similar to other terminals (iTerm2, native Terminal, etc.) on the same SSH connection.

Actual behavior

Colored output with Unicode box-drawing characters (the Cgroup: process tree section) takes ~13 seconds to render. Timing data below shows nearly all of that time is spent waiting (not CPU-bound), which points to a rendering/output-parsing bottleneck rather than a slow remote command:

$ time sudo systemctl status jellyfin
[... colored output with Cgroup tree ...]

real 0m13.145s
user 0m0.008s
sys 0m0.020s

With SYSTEMD_COLORS=0, the same command returns in under 1 second with identical user/sys times, confirming the remote command itself is not the bottleneck — the delay is isolated to Warp's handling of the colored/Unicode output.

Additional context

This appears related to ANSI color and/or Unicode box-drawing character rendering, since output volume alone (tested with journalctl -n 50 --no-pager, uncolored) does not trigger the slowdown — only colored/boxed output does. Happy to provide a screen recording or asciinema capture if useful.

Operating system (OS)

macOS

Operating system and version

macOS 27

Warp Version

No response

Warp Internal (ignore) - linear-label:7a739baa-09c3-499e-a0c9-a1a16c090597

None

Warp Internal (ignore): linear-label:b8107fdf-ba31-488d-b103-d271c89cac3e

None