Opening chat puts chat hotkey character into textbox

Pressing my chat hotkey ("t" or "/") opens the chat window and occasionally will place the characters "t" or "//" (because the backslash key inserts a slash automatically for commands), respectively, in the beginning of my message.

I've turned up the repeated key delay setting all the way, it takes a solid 4-5 seconds for my keyboard to start repeating on any other text box.

It does not matter how slow/fast I press the key.

Please let me know if you need any additional details from me!