My Client Sent a "GG" and Surrendered a Match

Is this a new “surrender” hotkey feature? I could not find any information on this regarding SC1. I was playing a match with a friend and at one point my screen went black for a few moments and the next thing that appeared was the “lost” score screen. The friend I played against reported that I wrote “GG” and then surrendered which I did not do. I never capitalize my “gg” anyway.

I have the screenshots of the “GG” and have uploaded the replay and the map (Blue Fighting Spirit) to “WeTransfer” but I can’t include links in the post so give me further instructions if I need to send you those.

Can someone confirm that this is some sort of a feature or am I hacked by a prankster? I don’t know which seems less likely.