I am experiencing a very strange issue with the attached LTC4418 power path controller design. I have one instance, where the controller does not switch off path 2 when path 1 when it is enabled. The circuit is looking for 12 (or 24V) from a car battery as the primary source, but has an internal 7.2V battery for backup. On this particular board, path 1 is energized, but FET for path 2 stays on - resulting in power being sourced directly to the battery. The battery is not rechargeable, so this is very bad.
To top things off, if I connect a power supply instead of the battery, the issue does not occur, and the circuit works properly. The LTC4418 has been replaced and the issue stayed the same, the battery control FET (Q2) has also been replaced - also with no change in the behavior. Attached are two scope shots presenting both cases. Please advise if you have any ideas to develop this further.