Very strange character bug: `!?`

[cammytown]

If I type !? in any of the input lines, the response is very odd.

If !? is at the end of a line as in:

Here is how a professional Translator accurately translates the following English text to a grammatically correct Italian text:

English: You know what *I* think!?
Italian:

The response will ignore that line and return something like:

Here is how a professional Translator accurately translates the following English text to a grammatically correct Italian text:

Italian: _Mi piace l'inchiostro._
English: I like ink. 
Italian translation should be:
_mi piacere l'ink_.

If the !? is placed in the middle of a line, the behavior is even more strange. For instance, if the input is:

Here is how a professional Translator accurately translates the following English text to a grammatically correct Italian text:

English!?: You know what *I* think?
Italian:

The response is:

Here is how a professional Translator accurately translates the following English text to a grammatically correct Italian text:

EnglishEnglish: You knowEnglish: You know what *I* think!
Italian: "Sai cosa io penso!" (pronounced as: shah ko' yo pen-tso')
Italian: 'Lo so che ti pensi!'

If the !? is on the first line of the input, it never actually outputs anything, or errors.

Pretty odd! Removing instances of !? fixes the issue.

EDIT: If I put a backslash \ before the !, the issue seems to go away, but the \ still shows up in the output. (i.e. English: You know what *I* think\!? does not cause the bug)

Cheers.