With those types of case fittings its easy to get the mechanism back in not quite straight. Do you know how to tell if a clock is in beat? The tick and tock should sound even, if the beat is uneven the clock will stop. If the clock is put in beat on a perfectly level surface and you then move it to a shelf etc that is not level you will find the clock will stop, each time it is moved from shelf etc to work bench you can guarantee 8 out of 10 times the beat will need re-adjusting.
Hope this helps,
p.s. with the mech on its side like that its hard to see what is wrong with the striking mech, can you take a pic with the clock mech upright rather than on its side?