Many of the owners of Transformer Prime Tablets were reporting an issue about the random lockups after they updated their device to Android 4.0 Ice Cream Sandwich. This issue has been noticed when more than 400 people replied in a thread regarding this issue on XDA Developers forum.
Now Asus is working on the new update and it's expected that it'll going to solve this bug. Releasing date of the update is expected in February, where the actual date has been announced officially.