FC Custom Tactics and Player Chemistry

What happens with player's chemistry if in certain tactics player comes to be in off position?

For example, I saw a lot of youtuber videos when they start in 4-2-4 formation for example, but they also have 4-3-2-1 formation as well and when they re-arrange specific players in the second tactic those player would be off chem because they are in wrong position.

Is this the case ot the game only uses chemistry set in the initial (main) formation?

Thank you.