Is it possible to actually give Mitch anything after having the condition talk with him? There's no option to do so, just the grayed-out condition button.
When I try to give her a Terran dildo it gives the 'You reach into your pack and search for something Olympia might find appealing' message and she doesn't get it.
If you still can't get the changes to stick you can also try using the export function and then importing the saved file from the main menu of the game.
When you load your save in CoCED you choose a file from Local or LocalWithNet.
Anyway, what are you using to save edit? Knowing that might help narrow down the problem.