Unstable connection/player downgrade

I lost a bunch of games in FUT Champs earlier today and still managed to have fun. Why? Because I played against great players in competitive games. Fast forward a few hours and I log in, hoping to pick up where I left off. Unfortunately, that was not the case.

I still managed to lose more games, but it felt like the same old situation. My players feel like they have been downgraded until my opponent takes a lead. In one match, I took an early 2-0 lead. Then all of the sudden my players couldn't complete simple passes until after he scored 4 goals. Zola, who scored a finesse shot from range, couldn't hit the target anymore. One shot went wide, and the other looked like it was straight at the GK. I didn't see my opponent make any subs or pause for tactical changes. It simply feels like someone turned a faucet on and off with regards to my players' skill.

It was even worse because at one point it felt like I didn't have control of my players. I switched from my RM to my CB to cover the ST making a run. He continued running straight toward my goal even though I had my stick pointed in the opposite direction. Players are not making tackles when press the button. They always wait until the after the player passes and tackle from behind, resulting in a red card. A few days ago I had a situation where I was controlling my RB and switched to my CB. Then my RB runs straight into the ST and causes a penalty.

I've read online that unstable connection can cause some gameplay/player performance issues. Is that what this is or is it something else?

Again, I don't mind losing to better players, but this feels like I'm losing to the game.