Zoom is crashing MacVim :(

This is a duplicate of this SE question

If I open Macvim, everything works fine, unless I zoom in (using Cmd+"+").

If I do that, then I get a strange black boarder around the added bit of the window and the whole thing freezes.

This is what I see:

(except, bizarrely, it isn't, because I see a black boarder, the mac screenshot shows a light gray one, and the image uploaded to Github mysteriously makes it white, which suggests there's something wrong with me)

...and there is a 40 second video of the problem here: https://youtu.be/cjKWRGLSWTk, which, thankfully, shows the same black border I see. Thank you YouTube.

This appears to be part of a few linked bugs on MacVim, I have quite a lot of trouble with the display not refreshing if I've changed the zoom level while the app is already full-screen and that's quite frustrating.

What information can I give to help you replicate this?

Reproduce the issue in MacVim by opening a window and zooming with Cmd+"+", then compare the freeze and border with the linked Stack Exchange question and video. Done means zooming no longer freezes or crashes MacVim and the window redraws correctly.