Honestly, I've never seen that message before. Backup your game, then try going on vacation and see what happens.
Took your advice, backed up, and tested. (Should have done so to begin with) And despite what that message said , the traits did not disappear. So no worries about that so far.
I've gotten the message as well. And I could only add a maximum of 3 more traits to the person, (8 total) which sucked. I too use the supercomputer and awesomemod.
I only just barely noticed this,but tried stuff out on it. I was able to just "Clear" the traits off of the sim all together, and then added 22 with the mod. it accepted, and they stayed.
Looks like a case of tight pants on the non-awesomeware, soldier.
I'm completely aware this all started by having the two mods together. I had guessed this was something that was part of the supercomputer, and guessed if I had removed it, I wouldn't have to worry about the message. Though I didn't start this topic to ask for help in getting the message to go away, or how to fix anything. (The answer for that I realize is just to take out the extra mod)
The whole thing just made me curious is all, and was just looking for some enlightenment. The fact there was a message at all about max traits and vacation, made me wonder if having too many traits would cause a problem, wondered since AM has no such message if the problem was insignificant, or not there. And wondered if the two did conflict, just how that was possible, and how it was supposed to work, it hadn't made sense to me.