#5229 [Bug]: Local TerminalView input becomes severely delayed while SSH remains responsive on Android 16 / ColorOS

[Bug]: Local TerminalView input becomes severely delayed while SSH remains responsive on Android 16 / ColorOS

Problem description

After the Termux UI has been running for some time, character input in the local TerminalView becomes extremely delayed and can become almost unusable. The shell and PTY are still responsive: connecting to the same Termux environment through SSH on localhost works normally while local on-screen input is affected.

This has reproduced more than once. Reducing the transcript size and enabling character-based input did not prevent recurrence.

Steps to reproduce

The exact trigger is not yet deterministic:

Start Termux and use an interactive terminal session for an extended period, including a program that produces incremental terminal output.
Continue using the on-screen keyboard.
Eventually, typed characters are severely delayed or appear not to be accepted.
Connect to the device's Termux SSH server and interact through SSH.
SSH input remains responsive while the local Termux UI remains affected.

Expected behavior

Local keyboard input should remain responsive for long-running terminal sessions.

Observed diagnostics during the faulty state

Termux remained the focused foreground activity.
Android's served view and served input connection still pointed to com.termux.view.TerminalView; the input connection was not marked deactivated.
dumpsys gfxinfo com.termux reported:
- Number High input latency: 6341
- Number Slow UI thread: 136
- Janky frames: 144 / 3917 (3.68%)
A stack snapshot caught the Termux main thread in android.os.MessageQueue.nextLegacy, waiting while acquiring an object monitor.
TermSessionInput itself showed negligible CPU usage.
The app was not under memory pressure and there was no ANR.
SSH input continued to work normally throughout, suggesting the shell, PTY, and backend process were healthy and the issue was isolated to the local Android UI/input path.

Configuration already tested

terminal-transcript-rows = 1000
enforce-char-based-input = true

Both settings were loaded before the issue reproduced.

System information

Termux application version: 0.118.3
APK release: official GitHub build
Android version: 16
Device: OnePlus PJA110 (ColorOS)
Architecture: aarch64
Kernel: 5.15.180-android13
Termux target SDK reported by the system: 28

I have intentionally omitted raw process listings, environment variables, logs, and full thread dumps for privacy. I can collect a targeted trace or provide specific sanitized diagnostics if maintainers request them.

Additional observation

The issue affects only interaction through the Termux app UI. Localhost/remote SSH access to Termux remains responsive at the same time, which provides a reliable A/B comparison.