Sure, we found the reason and it's already fixed in v1.3.2 .

Do you have a quick fix for this we could put in place in the meantime?  Thanks for your help.

You should edit the /wpforo/wp-hooks.php file.

Find this line:

$subject = strip_tags(str_replace($from_tags, $to_words, $subject));

Change to this:

$subject = stripslashes(strip_tags(str_replace($from_tags, $to_words, $subject)));

Then find this:

$message = str_replace($from_tags, $to_words, $message);

And change to this:

$message = stripslashes(str_replace($from_tags, $to_words, $message));

Please note: you should do this five times for each one, there are five same codes.