That is intended behavior as the code here indicates. Whenever you enter another window such as a terminal and it's not a floating window then zen mode exits.

I see.

I can see how this would be helpful in some contexts like opening nvim-tree; but in this case isn't there a way to get around this behavior?
or at least some hacky way to get the job done?

In my workflow I tend to open and close the terminal a lot and so having to turn on zen mode every single time pretty much defeats the whole purpose of it.

Just open your terminal as a float window instead, since that doesn't seem to quit zen mode?

Yes I ended up doing that thanks for the suggestion.

For anyone wondering how to do it, your snacks config should look something like this:

opts = {
    terminal = {
      ---@class snacks.terminal.Config
      ---@field win? snacks.win.Config
      ---@field override? fun(cmd?: string|string[], opts?: snacks.terminal.Opts) Use this to use a different terminal implementation

      win = { position = "float" },
    },
  }

By doing it this way, you're changing the behavior for all terminal windows that are created with Snacks. This might be the behavior you want or might not. For example lazygit also opens in a terminal window but it's opened in a float window either way by default.

Personally I prefer to put these custom changes into styles myself, because that way only the windows with the selected style will be affected. So, I do

opts = {
  styles = {
    terminal = {
      position = "float",
    },
  }
}