Able to verify that this occurs in creative mode and creative-set-survival.

Uploaded 2 screenshots that were taken 2 seconds apart. There are two fireballs that are "stuck" towards the center of the images. The third image (without debug overlay) was taken from my Forge development environment, but shows at least a dozen such fireballs--it would be impossible to generate this image if the fireballs were not stuck. I noticed this error when creating an item that allows the player to shoot fireballs and was rapidly quitting out, tweaking the code, and relaunching.

Reproduce:
Enter the Nether, have a ghast shoot a fireball at you. Before it enters within a certain range (~2 chunks?) hit Esc and quit to the main menu. When the world is reloaded, the fireball will be stuck. There's a narrow radius where this does not occur, roughly 32 blocks out (difficult to verify) where they will reload properly, which is why I spawned the ghasts so far away.