Window keeps popping up when I enter "* " (asterisk + space)

I’m new to this Scrivener business. I’m writing in Markdown and writing up a list of bullets. Whenever I enter an asterisk and hit the space key, another editor window pops up.

It doesn’t happen consistently but often enough that it’s quite annoying. I can’t find this behaviour mentioned anywhere else. Any ideas how I can turn it off?

Thanks.