Something odd has happened in my game THREE times: Sim X learned all of the skills that come with AL, then when I order him/her to study the ordinary skills (i. e. Cooking) just maximizes the skill in seconds. So, in my game I had 2 children and 1 young adult that maximized all 7 skills in seconds. What's happened? Have the AL skills some sort of "perk" that makes this happen (I've heard of Physiology increasing Body, but the others, no)?

There's a glitch that causes Physiology to increase other skills as well. It was only supposed to be Body, but...

I haven't noticed Physiology to do anything other than body. I've had a few sims learn quite a few but never all the AL skills so I don't know about that. My sims have to roll the want to skill those and I guess nobody has ever wanted them all.

Do you have the Apartment Life patch? If I remember right, the patch fixes a glitch where Physiology affected every skill instead of just body.

Almost everything in alfixes was fixed in later patches, so gummilutt made a mod to be used instead of alfixes that fixes only the Physiology-immediately-maxing-Body glitch. The reason you may want to use this instead of alfixes is that alfixes is more likely to have conflicts with other mods.

Not necessarily, Orilon. My game is fully patched, and having a Sim learn Physiology will still mean they will more or less instantly max out their Body points once they engage in an activity that increases Body skill. I believe Cyjon has a fix for it...but I actually rather like this "benefit" of learning Physiology. So, I haven't fixed it, myself.

That said, I've never noticed any of the "Extra" skills conferring any speed-learning benefits on any of the other "regular" skills.

Fully patched with alfixes removed because it clashed with the simlogical school- my sims gain all body skills after learning physiology and I like it. One small perk seeing i use a slower skilling mod and it's only sims who want to learn physiology who gain it.

It was patched in AL, and then broken again in M&G. So that's why the patch fixes it for some and not for others.