Scroll position jumps hundreds of pages when scrolling up during/after output

Description

When scrolling up in the terminal to read past output, the scroll position sometimes jumps dramatically — as if scrolling hundreds of pages above the actual content. This makes it very difficult to review prior output.

This started happening after a recent update. It did not occur in earlier versions.

Steps to reproduce

1. Run Claude Code in a session with substantial output (tool results, code, etc.)
2. Scroll up to review earlier output
3. Observe that the viewport sometimes jumps far above the actual content area

Expected behavior

Scrolling up should move through the terminal buffer smoothly and predictably.

Actual behavior

The scroll position occasionally jumps dramatically upward, as if the terminal buffer is much larger than the actual content, landing on empty/blank space far above the real output.

Environment

• Claude Code version: 2.1.108
• Terminal: Apple Terminal 470
• macOS: 26.4.1 (Tahoe)
• Shell: zsh