This isn't a bug. Sometimes you don't notice the NPC Sims in the community lot or in the open areas around the active lot.
But the OP is saying that they should not skill up even if they do play chess or whatever as that is a significant change to the active family.
According to them, it only started happening after that May 2015 patch.
I don't know what the intention is but I understand where the OP is coming from.
Can you see if you can get an answer from a SimGuru on this issue?
I've already asked about this - unsuccessfully so far.
I do agree with you that it's likely working as intended. I've checked my own game since posting this and yes, they gain skill but it makes sense that they do just as it makes sense that they gain romantic relationships when they flirt with other Sims on community lots - even that is not appreciated by the player.
I haven't added this to the list and OP has also not come back so I don't really know how important that is. There's also no me toos so, I would just consider this abandoned as I do with all threads where the OP doesn't come back and no one else has reported the issue.
There so many active issues, why pursue something that one person had didn't come back about ?
It is working like this in my game and I thought it was working as intended that is why I would like you to verify. My Sims that are on community lots playing chess or fishing do gain skills when I am playing another household. If they prevent played Sims from gaining skills when they are NPCs but they still do, it is an issue.
