Here are my guesses on how a device can be cracked even if encryption is properly implemented:
-If a phone is already powered on and running, the encryption key can be discovered with a RAM dump.
-If a device stores it's encryption key in a "secure" chip on the motherboard, it can obviously be recovered by a determined enough hacker. I doubt that any phones actually store their encryption keys this way but hardware encrypted SSDs have. They were secure until they weren't.
-If a user opts for a pin instead of a longer password, this can be brute forced.