TL:DR The belt works as intended. I don't think it reduces all damage by .73. I think it only reduces bonus critical damage by .73. Thus 1.365 v 1.095 total damage reduction
1. The standard crit range of that weapon is: 22(1.5) to 32(1.5) thus 33 to 48. Which obviously is not accurate considering you got a crit for 50 without the belt. So there must be some rounding going on which would mean the actual damage range is ~35-50
2. The crit range with the belt on assuming 1.095 is 24 to 35. (~26-37 with rounding) If this were the case then your video shows the belt is broken.
3. However, I think the belt only reduces the bonus critical damage by .73 instead of all damage. Thus .5(.73) = .365. Thus total crit damage = 1.365. Accordingly the damage range with the belt on for that weapon would be 22(1.365) to 32(1.365) or 30 to 43. With rounding errors = ~32-45 Which fits in the range seen in the video.
If that is the case I think your video shows the belt is working as intended. And makes more sense because 1.095 reduction from 1.5 seems a bit strong.
On a sidenote the numbers that popped up on screen were always 1 less than the combat log.