CRT TV Color Bleeding while showing Small Picture with Black Border

[ABOhiccups]

I was playing Super Game Boy for SNES. I set the Border to Black only. A few seconds later. Two Colors are bleeding from 2 corners of the TV while showing Black Border on Super Game Boy. The Colors stop bleeding and change back to normal after I change Border.

Does anyone know is there a fix to this issue on CRT TV? Just post a link to YouTube Video or Tutorial Website.