Yeah I only play career mode and on World Class difficulty.
The defensive AI are ridiculously strong when playing against the computer but completely useless for your own team.
I've actually had one center in the pair of two move out of the way of a CPU attacker running into the box to create a huge gap between the two CBs and leaving the goal wide open.
That second clip the OP posted really just exemplifies it. Attacker just standing wide open between the two CBs who are just standing there passively, not making any attempt to close him down or block the pass.
