By default, Moodle ships with a default number of emoticons turned on — filters that turn text smilies into graphical ones. This is all well and good — the nuances of speech can be lost in the written words, and emoticons help with that — but it can cause problems, particularly with some of Moodle’s more obscure emoticons colliding with math terminology.
For example S(n) gets turned into an S with a “NO” icon. This can’t be disabled on the course level, but it can be disabled site wide, per this tracker item:
In short, you go to Admin > Appearance > HTML Editor and can then edit a list of emoticons. Some of these are pretty obscure, and (I think) unique to Moodle:
- (y) = yes
- (n) = no
- (heart) = heart
- (h) = heart
I’ve disabled these in our version of Moodle to avoid collisions between math terms and emoticons.