Here's my 2 cents:

1. [Fact explained in the film]: The mimics operate on a hivemind network basis. Omega is the brain, everything else are mindless drones i.e. the Omega's mobile eyes, ears and claws. Therefore when Omega dies, the rest will follow suit as well.

There seem to be a weakness to this hivemind network. The Omega needs Alphas which serve as proxy mobile command centres to maintain close battlefield control. Therefore Alphas are important - if an Alpha die, the local network would be crippled (dies outright/becomes more difficult to control remotely), which is why the Omega loops whenever that happens.

Based on this info, anything happening in the battlefield is first stored in the Alphas memory first, before being transferred to the Omega on death.

2. [Assume]: Only the brain/independent thought/high-level autonomous response which is only capable by the central nervous system can (i) save a check point at X no. of hours prior to death and (ii) restore time to the check point. This also means that only the Omega can trigger the loop, as per (1).

3. [Assume] One can only save check points based on one's own experiences/memory i.e. Omega can only create checkpoints from battlefield data received from Alphas. If the data is not transferred to Omega and backed up before a loop occurs, the data i.e. memory is lost.

4. Based on this assumption, this means that Cage is capable of recording battlefield data/memories in his own brain without using a proxy, since he is the "brain" himself, so to speak.

The Omega on the other hand will learn nothing regarding the battlefield/how to change the outcome if it does not receive any data from Alphas and thus has no backup copy to analyse from: a time loop just happened out of its control and it is left blind/powerless.

5. [Assume] Besides Cage, the Omega also retains its memory after the loops (since it only loses the battlefield memories, not its own base memories). Unlike the novel/manga where the mimics know who is the illegal looper, the mimics in the film do not know who is triggering the loop. That's why after so many out-of-control loops, the Omega realised someone is intentionally causing the loops and therefore sends a false image signal through the hivemind network that only entities connected to the network (i.e. mimics) including those partially connected (i.e. humans who have absorbed mimic blood) can see in order to lure the illegal looper out.

6. Cage sees the image (false location @ German dam) & falls into the Omega's trap.