Hi nossr50,
We have another user who has reported this same issue at the following link: Serialize causes crash - Programming & Scripting - Epic Developer Community Forums
We are currently looking into the issue and hope to have more information soon, but please refer to the linked post so that we can get all of it in one place. You can feel free to comment on that page as well to assist in finding this issue if we have any questions we need to ask or if you simply have more information to provide.