cheat or mistake?

(An issue that occurs in Ultimate Team Rivals mode.)
This has happened to me twice so far in the game. While the match is going on normally, my team suddenly resorts to strange tactics and substitutions, exercising all their rights. The strangest thing is that the team's reserve goalkeeper starts playing in midfield or as a forward, while the forward moves to defense.

This is where the real bombshell explodes. Normally, the team has used all its substitution rights. Somehow, towards the end of the second half, the team reverses all its previous substitutions, and the players who left out are rejoined. Based on this explanation, I'm asking the question in the title.