Had the Same expirience and made a solution myself. the trick is easey but needs you to do some work of your own... I fixed it by useing the CoSMOS-Programm from this side. you also can use Cheat Engine instead, but CoSMOS is a lot more suitable. I could not find an easey way for it...
If you use the Trainer for Unl. Stamina, after you disable the trainer-option or teh trainer itself, the stamina is not unlimited, it is just to much to use up (i think it was increased to 9.999 points or something). So, after you disable the option, the stamina DOES de- or increase by using skills, equipments or potions. remember that for the trick.
my trick was:
First; do unequip all skills/talents/equipments that in- or decrease your stamina.
If you haven't changed your stamina yet, you got to search for the value of your max-stamina-points and remember the value. then change it with the trainer or an item or else and search for the new value - you will find the max-stam. value immediatly. remember the amount and when you want to go back to your standard-max-stamina just enter the amount and freeze it in the CoSMOS, save the game, and load it. tht fixes it.
if you have already used the trainer and changed the stamina do the same except; you got tu equip or use any item to increase or decrease your stamina und search of the changed amount - and track it back, change and - done.
Just tested the latest trainer with the latest version of the game (all DLCs) and it work as expected, flawlessly 🙂
You need to run the trainer as administrator, always, it's imperative!
You'd better to whitelist the trainer's executable in your anti virus instead of shutting it down, most of them keep working in the background even if it's telling otherwise.