Technically, this doesn't fix the problem, but basically, it does.
If you launch your game and click on the save you wish to enter, before doing so, I recommend using the "testingcheatsenabled true" cheat code. After use, enter the game and once loaded, go straight to the LTR tab. -(For either plumbot or sim!)- You can 'left click + right click + ctrl' on the treasure cheast until you have 10,000 LTR points. -(Sadly, you can't hold these keys down)- Go into the menu of different rewards, scroll down and purchase 'Trait chip bundle'. A box will appear in your sim's inventory and you have the option to open it if you click on it. -(It's like a Christmas present!)- You will receive a bunch of different trait chips, hopefully with the ones that you lost. If you don't get all the same chips, keep repeating until you do.
I had this problem once and remembered purchasing a bundle the other day. I used the cheat to get the LTR points in able to fix my plumbot.