If the attacker manages to obtain multiple disk image of an FDE encrypted drives over time, FDE may leak the location and sizes of the sectors that changed between the images.
Depending on what other information that the attacker already have available about you, they may be able to infer what kind of information is was changed.
Also, XTS which is the cipher mode most commonly used for full disk encryption leaks the penguin over time because of the way the tweaking works. Writing the same data to the same block will write the same encrypted block. If a certain block flips between two possible values, they may be able to infer when that flip happens and possibly which value turns into what. More information on this.
Finally, this is probably not relevant for the forensic scenario, but since XTS is not authenticated, a sophisticated attacker may also fiddle with the encrypted disk to modify the data in it.