The hour hand faulty movement is caused by the Intermediate date wheel not having anything to anchor it in place like a regular 2836 and 2824 have. The movement can be fixed, I just completed one recently.
The jump click was epoxied together, an IDW support arm installed, and the movement mainnplate filed to accommodate a 2836 date corrector (double corrector) so the quickset date feature is restored.
Here is some more info from a previous post
There are two points of potential failure in these movements.
1. The jump click spring can break. The spring is located inside the two part GMT wheel, which is held together by the collet. The two halves of the GMT wheel rotate independently if the click spring is intact. If it breaks, the two halves can be epoxied together. It makes no difference if the broken click spring is left inside the GMT wheel for the gluing, although it can act as a containment border for the glue. Once the halves are glued, the GMT and hour hands will be forever synched, but will retain their proper rotation periods (hour hand 2 cycles per 24 hours, GMT hand 1 cycle per 24 hours).
2. The Intermediate Date Wheel (IDW) has no support arm on it in this movement like it does in a native 2836 and 2824. It can get cocked up out of position separately from the click spring breaking. This is due to additional forces placed on it by the datewheel driving wheel around the times of date change (10PM - 2AM). The result is the hour hand becomes stuck or lags behind or is not responsive to crown movements for as long as the IDW is out of position because the hour wheel has become disengaged. Sometimes the IDW will settle back down into position, sometimes not. The potential for this flaw to occur increases when the GMT wheel is glued together because the click spring is not available to absorb any of the pressure exerted on the solid GMT wheel. The fix to this flaw is a custom made IDW support arm fitted underneath the datewheel cover plate.
So, even if you have a spare GMT wheel with an intact click spring, it will not prevent the IDW flaw from occurring. I have fixed that flaw in several of these movements where the click spring never broke. The IDW flaw may never occur, but it is not uncommon.
Here you can see a normal alignment of the IDW and the hour wheel (which sits atop the GMT wheel), and then a pic of the IDW when it gets displaced. This causes the teeth to skip or disengage altogether.
Some pics of the mainplate mod