I’ve been noticing a problem with slow or stuck transitions recently. Seems to happen on certain apps only like Slack, regardless of its position on the grid. I have transitions disabled because I like the space switch to be as fast as possible. Going back and forth in apps like the browser and the terminal is fast and snappy but it gets stuck or has a bit of delay in apps like Slack. It doesn’t happen always either but its fairly frequent.
I’m on Mojave 10.14.6. Let me know if I can provide more info about it.