I've started playing Final Fantasy VII a while back and I just reached the 68th floor of Shinra HQ... There, instead of facing 'Sample: H0512', I fought a single Zenene... Thinking it was just a simple bug, I defeated it and went on with the game... Later on, I discovered that (probably because of this bug) all Boss battles where rolled back... To make it clearer, I fought 'Sample: H0512' (when I enter the elevator with Aeris) when I was supposed to fight 'Hundred Gunner' and, later on, I had to face 'Hundred Gunner' instead of 'Rufus' (using just Cloud instead of my party, probably because the game thought I was fighting 'Rufus')... Finally, I didn't even encounter 'Motor Ball' after the motorcycle chase... Thus, I decided to ask for help in order to resolve this issue.
I use these modifications:
-Final Fantasy VII Remix [2.5.1]
-Aali's custom graphics driver [0.7.10b]
-Team Avalanche's GUI [2.0.8]