Hopefully this is in the right area!

Well, sometimes when i hit enter to chat, a bunch of numbers, at least a hundred just show up in the box and i cannot erase them to type anything else. Sometimes i have to enter them at least 15 times to get the chat to work again. I have to forewarn my team before it happens almost everytime i play. Is this normal, or is it something that can be fixed? Its just really annoying! Thanks!