2nd team coaches are sometimes available for 1st team training - sometimes they aren't

[Feron]

in several saves, at some point I was allowed to use my 2nd team's coaches for the 1st team, allowing for a very specialized training. In one save even the U23's coaches.

But in many other saves this is not the case and I don't see any pattern or reason for this. Can anyone help with this?

[destroyed2011]

I could be wrong, but I think it depends on the country/ league you are playing in. For example, I'm pretty sure U23 coaches can take part in 1st team training in the Premier League. However, some countries/ leagues don't allow this.

[Hovis Dexter]

It is my understanding  that if the second team is called "second team" or " reserve team" or U23s then the general coaches will also coach the first team. If, however, the second team is the U21s or younger then the coaches are not available to assist with first team training.