ITerm2 Vim Background Transparency Changes Based on Battery Power Source

• iTerm2 version: Build 3.4.3
• OS version: macOs BigSur 11.1 (20C69)
• Attach com.googlecode.iterm2.plist

Detailed steps to reproduce the problem:

1. Setup vim and install any theme with a preset background color
2. Set ITerm2 -> Preferences -> Profiles -> Window -> Transparency to some non-zero value
3. Observe window transparency with power plugged in vs. on battery.

What happened:

Plugged in: Battery:

Observe that the transparency on window to the right remains constant, while the transparency on the window to the left changes unexpectedly. I tried this with multiple themes.

What should have happened:

The background transparency on battery is much more opaque than background transparency when plugged in. I expected them to be the same.

It's very possible that this is an expected behavior from macOs powersaving or isn't an issue with ITerm2 specifically. However, I couldn't find any discussions/documentation highlighting this behavior.