md(1) crashes my cell. The completion of typing the last ')' in "md(1) causes the `(1) to become repeated twice in the cell and cell/page causes an error and page crash.
Yikes! Sorry Brooks, and thanks for the report. I can’t seem to reproduce that; could you make a screen recording of this happening, with your browser’s developer console open to show errors?
I’m just guessing from the appearance of that “Save” button but it looks like you’re on a Mac, in which case you can start a screen recording by pressing ⌘-Shift-5. To open the developer console in Chrome, Safari, or Firefox, press ⌘-⌥-I and click the “Console” tab. I’d also be happy to screenshare with you to try to reproduce and diagnose.
If it makes you feel better I can’t reproduce it from scratch and that problem cell is gone. Clean notebook and clean cell and I can’t reproduce. But basically the behavior was such that adding the closing parenthesis to (1 in the example above produced the second `(1) that you see in the screenshot. And that was with autocomplete off. With autocomplete on or off for parentheses completion I can’t reproduce.
So sleep well for now 
I’ll screenshot next time something happens. I’m invested in Observable and I’ll do a better job of communicating the bugs if I encounter any. Plain english for odd bugs is sometimes less than sufficient
Haha no worries about the plain English bug report, we welcome those too! I’ll keep an eye out, and you know where to find me.