Ingame Chat puts ^ symbol before any character i press a key

As the title says, whenever i try to write something in the ingame chat, it acts like i would press the ^ key (german keyboard layout, the button over "tab" ) before every other button i press. My brother has the same issue on a completely different computer. It started after Patch 4.2 or 4.1X i believe and occurs in every game mode. The chat functions in the client and all other programs and games on my computer work fine though.