It looks like the issue occurs when transitioning between areas.
In some areas, the trainer's unlimited health option won't work at all.
Well it works fine on my end whenever I tried it.
It doesn't deactivate, it just stops being effective. I started a new game, everything is the right version, and I can't get to the fog wall before stamina stars dropping and health drops with each hit. Trainer then can't be deactivated or reactivated. Reboot, restart CH and Steam and DS3, exact same experience.
Does your game version match the trainer version? Are there any special instructions that need to be followed? Are you running Aurora as admin? Not doing that can cause issues for a lot of trainers. Did you extract Aurora as opposed to just running it? Do you have the newest version of Aurora? Have you reinstalled/verified the game files? Have you restarted your computer before trying the trainer again? Have you set the anti-virus exclusions for Aurora? Are you opening the game from a supported launcher? Are you playing a beta version of the game? Are you using mods?