Omega cal 1611/1320 hour wheel failure?

[AlexeiJ1]

Hi Guys,
I've been rebuilding a 1611 Omega Chrono Quartz watch, I've finally gotten it working.

Now there is a curious flaw, and it persists even after two total strip down inspections and ultrasonic/one dip/oiling.

At 8pm every night, just after 8:45pm, hour hand stops moving at the halfway point, the minute hand keeps going, and then the watch loses an hour the next morning.

This is an omega which has the jump hours setting (you pull crown and the hours jump when you turn the crown).

There is a thread on another forum where the hour wheel has failed on a GMT model.

My 3 possible differential diagnoses are:
- Magnetized parts somewhere upsetting the gear train

-Weak magnets on the minute wheel needing replacement (most likely because if you look at the design, there must  be some resistance in the geartrain that occurs at 8:45pm).

-Wear or cracks somewhere that I cannot identify, or potential freeplay on the hour wheel

Any thoughts?

The craziness is that I just sold a NOS 1320 movement on ebay because I thought I had sorted this bugger!!!!!!!!!!!!