Slow line drawing while scrolling with k9s in iTerm (but not Terminal.app)

Thanks for filing an issue! Please answer the questions below so I can help you.

• iTerm2 version: 3.4.8
• OS version: 10.15.7 (19H1323)
• Attach ~/Library/Preferences/com.googlecode.iterm2.plist here (drag-drop from finder into this window)
• Attach a debug log, if possible. Instructions at https://iterm2.com/debuglog
• Attach a screen capture video if it would make the reproduction steps clearer.
• Are you reporting a performance issue, excessive CPU usage, or a hang? Please attach a sample. Instructions at https://gitlab.com/gnachman/iterm2/wikis/HowToSample
• Are you reporting a crash? Please attach the crash log. Instructions at https://gitlab.com/gnachman/iterm2/wikis/crash-logs
• Are you reporting excessive memory usage? Please attach a heap analysis: https://gitlab.com/gnachman/iterm2/wikis/heapshot

PLEASE ATTACH YOUR PLIST FILE FOR BUG REPORTS! Seriously! I'll probably ask you for it if you don’t.

Detailed steps to reproduce the problem:

1. Open k9s
2. Go to a view with a ton of lines
3. Scroll until the screen is actually redrawing
4. Experience pain

What happened: drawing of new lines is very slow

What should have happened: it shouldn't be slow (it isn't in Terminal.app)

com.googlecode.iterm2.plist

All debugging files, including debug log and screen recording: https://www.dropbox.com/s/0mvrbgcv2x7w5o1/iterm_bug.zip?dl=0

stats.txt