Full Screen should capture whatever your display is set to; in this instances 1920 x 1080. If you were to click on Custom and then enter parameters (or drag mouse) to define something other I could see this happening. Can you confirm that Full Screen capture is in effect and not something Custom? I use Custom to shoot 1280 x 720 towards YouTube deployment...
If it is set to use full screen there may be a corporate desktop setting in play that we're not aware of.
In this image it shows 1280 x 720 in the upper left hand so my assumption was that it recorded in that resolution but maybe that's a bad assumption.
Click the recording dimension window first.
Then select Original Recording Dimensions. It should indicate 1920 x 1080 if it was recorded that way.
What's happening is you are editing at 1280 x 720 and you don't want to do that.
You always want to edit, record and produce using the same dimensions to achieve the best results.