Escape sequences like ":12:30:" exist in the replacement table of AutoCorrect. However, as soon as the second colon is entered (like ":12:"), the text is replaced, and no change is made for the last few characters.
you are right. you reported it first however there's more informations and workaround in the other bug report. so I mark this as a duplicate and continue discussion over there *** This bug has been marked as a duplicate of bug 93233 ***