From an old bug report (sent directly to devteam, June of 2017): wand or scroll of create monster becomes discovered if it makes a mimic that is concealed as an object or as furniture within the hero's view. Fixing this in the general case [when does seeing a mimic as something other than a monster mean that the mimic is being seen?] is a massive can of worms, but fixing this specific case is trivial.
20 KiB
20 KiB