Catalina 10.15.1, MacVim 8.1.2234 full screen before sleep, full screen is broken on wake

Describe the bug

After waking the computer up, MacVim which used to be full screen is no longer full screen. The "full screen window" where MacVim is supposed to live is still there, but the MacVim window itself is not full screen, and exists on a Desktop "window". I'm not sure of the correct term here, but by "window" I mean the full screen switcher which appears at the top of the screen when in what used to be called expose mode.

The MacVim window is mostly unresponsive -- keypresses do not have any visible affect, and clicking the window doesn't either. When using the macOS application switcher, the "full screen window" is activated when attempting to switch to MacVim, but the screen is black.

If only one MacVim window is open, sometimes the green full-screen button works and will put the window back. Sometimes not. I believe that when multiple windows are open, the green full screen button never works.

Often the only way to get back to a working application is to force quit macvim.

If the terminal with which I launched MacVim is still open, a message like this is printed:

2019-12-23 05:57:59.389 MacVim[10882:9934680] not in fullscreen state

To Reproduce

This is a bit of a head scratcher for me, but I believe I'm able to reproduce it intermittently in this way. I see this bug several times a week, but it is not consistent.

• Open a file in MacVim - I usually do this with mvim in the terminal.
• Full Screen MacVim
• Put computer to sleep for a while -- short sleeps don't seem to trigger it.
• Wake computer

Expected behavior

The application should not lose it's full screen status.

Screenshots

I will attempt to take a concise screen recording next time I see the problem.

Environment:

• Vim version 8.1.2234
• OS: macOS 10.15.1 (19B88)
• stock macOS terminal.

I cannot see how it would matter, but my vim config is on github as is my list of plugins

Start by reproducing the intermittent failure with MacVim 8.1.2234 on macOS 10.15.1: launch a file with mvim, enter full screen, sleep the computer, and wake it. Compare behavior with one and multiple windows, including the “not in fullscreen state” message. Done means MacVim remains responsive and retains full-screen status after waking.