This is a very, very annoying bug and seems to only affect the right border next to the scrollbar. Everytime I miss the scrollbar and grab the right border and try to scroll down, either 2 things will happen:

1. The fullscreen resizes to half size 2. The grab icon will automatically half size and grab the whole window. Sometimes this results in the window getting thrown to a separate desktop (I am using Gnome- Classic)

It would seem like the top bar grab has extended its way all down to the right border, but with an added annoying feature.