https://docs.moodle.org/26/en/Embedded_Answers_%28Cloze%29_question_type#Format isays
> If the correct answer contains } # ~ / " or \ you will have to escape them by putting a \ in front of each such character.
escaping of # and } works ok, {:SHORTANSWER:=\#bla{\}}
would need entering: #bla}#
Tilde needs to enter escape char in answer box, otherwise it doesn't work,
except for the very first character of answer -- it can be given without backslash
{:SHORTANSWER:=~~bla}
would have two answer alternatives: ~ and bla
{:SHORTANSWER:=~\~bla}
should have answer entered as ~\~bla , but not ~~bla
Backslash and quotes does not need to be escaped at all!
{:SHORTANSWER:=\ \# \\ \n \"}
answer should be entered as: \ # \\ \n \"
ps.: I have Modle 2.6
At least - wiki should be updated, I guess