training "problems" and bad player ratings

Hello, recently i bought 18y.o. 4* player expecting from him to train fast but after a day i realised he was gaining skill points with same speed as my 28y.o. player wich i find very inusual..actualy only players wich are originaly from lvl1 team are training fast others that i bought are more medicore or bad.
Is that normal? :)
another thing is for last 4 matches my players are just..lazy lol. after the match(oponent is equal or usually worse)they are rated mostly 5-6 some 7 rarely 8 and they're losing morale more often than before. example: 2 points worst player defeated me 0:1, i had 4-4-2 he had 4-3n-1-2 my ratings terrible, his great..it's like my players don't wanna play with eachother lol :D
why is that? just bad luck or something i missed ?
tnx a lot for answers :)

p.s.: i just checked, he is 19y.o. and gaining 50% of average gain when training..strange

Yes, not all players are fast trainers and it's normally the ones with lower market values that train slower, a lot of players are your 2* ducks that other managers get when promoted from the youth system and sold.