Has the age group for training speed changed?

[HeavensAAA]

I bought a 3* 20yo today to do the quick 'Train a special ability' and he was terrible, 22% loss of condition training was giving me 1 symbol.
So I bought another one and he wasn't much better, around 5 symbols per 4 training routines.
Even a slow trainer at 3* used to be better than that. It does feel like the 20yo's have slowed down.

More than likely both you bought are also slow trainers. A few % drop in training efficiency won’t reduce that much amount of cones received. Maybe. 2-2-2-2-2 becomes a 2-2-2-2-1, but not 1-1-1-1-1.