When you are about to warn someone, you have to choose the warning. If you don't choose anything, by default the system selects the "Custom warning" value with "Apply warning points" set to 1 and "Points expire after" set to 1 month, also by default the system checks the "Start a conversation with..." checkbox. If you attempt to issue the warning without entering a title for the custom warning you get the following error message: "Please enter a valid title."
Well now let's get into the problem. On my forum I have various warnings, however none of them have a value of 1 point and they are not editable. There are some of them that expire after 1 month. The problem is that randomly (and rarely, let's say 1 in 200 warnings) some warnings that have let's say a value of 4 points and expire after 3 months are being logged as if they have a value of 1 point, expire in 1 month and the member isn't receiving the conversation.
For example I have a warning called "Bad behavior" that has a value of 4 points and expire after 3 months. Everytime a moderator issues this warning the member gets logged in his profile the warning for 4 points and a expiration date of 3 months plus he gets the conversation. However sometimes the member gets logged "Bad behavior" but with 1 point and a expiration of 1 month and no conversation.
I have asked a moderator affected by this problem and he told me that he issued the warning as always but at the moment when he issued it there were connectivity problems to my forum (i.e. it was loading slow, packet loss or unresponsive).
My theory is that when there are very slow/unstable internet connections the system gets confused and thinks that the moderator chosen "Custom warning" (1 point and 1 month) but since it is unable to detect a title for the warning (since the moderator in fact chosen another warning) then it fills the title with a random warning of those available at the ACP and since it also can't detect a value for the conversation title nor the conversation message then it doesn't send the conversation.