When in the nether and trying to hit back ghast fireballs on my 1.15.2 server, the fireballs don't get hit, and instead just go straight through your sword and hit you, or just continue past.

My friends in the server also have this problem as well, we can typically hit the first couple fireballs and then the rest after that are just broken and don't allow you to hit it.

Video too big to attach. Posted here: https://youtu.be/-z5V3pEBBOU