I’ve informed edX of these issues but saving them here for the record to timestamp when the problems were reported:
Dollar Sign Bug
When you use the dollar sign twice, it reads it as a very weird formatting character (renders as bold italic with no spaces).
I have tried various escape characters to stop this from happening but had no luck. Also I cannot find a help page for the markup language. This is a problem when you are writing about money.
H1 Header Text
There is something wrong with how the markup code renders for the header text designated by “=====” (H1).
It looks OK in the preview, but when you save the post, it recopies the post title in place of the header.
Example, typing “This is a header” with H1 markup renders as:
Another markup bug: Header Text
Actual text & preview: