DO NOT USE THE TRAINER ONLINE, THE TRAINER IS ONLY FOR SINGLE PLAYER USE ONLY
This would most likely need to be put in an update report to be looked at.
Also you mention it's related to the in-game overlay.
Does the trainer only work fine without doing auto inject of overlay or does enabling the in-game overlay overall after activation also work?
I was more wondering if it was instant crash upon activation of the trainer or if having hiding and showing the overlay did the crash.
Anyways you would have to report it as it seems like it might be a bug with the overlay for this game.
Please use the update notification system to report a game patch, update or to report that the trainer may not be working with the latest version of the game. If 3 or more reports have been filed, consider BOOSTING the priority of this title for a faster turnaround on the updated trainer.