I'll leave the original topic here:

https://answers.ea.com/t5/Bug-Reports/Player-career-mode-stamina-drain-Fifa-20/td-p/8605643 

So, a week and a half, maybe two weeks ago I started a new career with Fiorentina, the stamina drain I didn't realize it first but called my attention that some of the club's key players where not lasting the whole game (Chiesa and Benassi) but really didn't payed much of attention because it was still playable; the only thing I really noticed is that when you see the formations in the screen it would say "undefined". Two years passed in the career and I changed team to Leverkusen, and that's when yesterday I started realizing what was going on, at the end of the first half they were almost without energy, getting to the end of the game with no energy at all (several players).

Couple of days ago there was a new update I got into this forum and I read the topic that I left you before so I started a new one, I got  this time Real Sociedad to change league completely, fresh start after the update to see if it was really solved. And nothing, first friendly game of the season half time, half dead. Still the "undifined" in the formations too (at least in the leagues, UCL you'll see the names but not always in their right position.

I revived this account just to write this, hopefully the EA Team will noticed it because for now is unplayable. And probably we will have to start a new one after they fix it for like the 10th time this year.