If you have a worldborder with at least a distance of 16 blocks then the game wont reload your datapack. I tried that in many worlds and I even tried it when the worldborder is centered at 0 0. I put the datapack I used in here so you guys can test it for yourself. Just create a new world put the datapack in it and type /reload. Then the world will be in a freezed state.

Datapack Download [Cant Attach it... sorry]--> http://www.mediafire.com/file/mygpf51il3p1r17/aq.zip/file

Update: This only happens if your worldspawn isn't in the worldborder, so if you set your worldspawn in the worldborder you should then have no problems.