Turrets Stuck Building

I noticed a pro on the other team in the Turret Build menu. I walk up to him and stab him in the back, but before I killed him, he built a level 1 Lazor Blazor. The problem being that the turret building "shell" never came up. There was just a Lazor Blazor there, fully built instantly. This thing wouldn't shoot anything, and it couldn't be destroyed.

Also, I've noticed the flashing lights at the top of the turret building shell stay there even after the shell has disappeared.