Most of your new holes are going to be in lines perpendicular to those old ones. The old holes may give the mud something to grab into. Could be your mistake improved on traditional tape joint.
At least you caught yourself B4 you went to far and you didn't it wrong side out. I know a guy did that in a 16 X 24 addition I built for him. He said he thought the beveled edges had something to do with fitting over studs.
From that job I learned, when owner is going to do part of job, to first make sure owner knows how.
Measure twice, cut once.
Look at the nail, not the hammer. Watch the fence, not the blade.
If you hook your thumb over your belt you won't hit it with the hammer or leave it layin on the saw table.