I posted about using collars based on my interpretation that the crack was through the shell at the weld. For the plate to crack off at the outer edge of the fillet taking the entire fillet off intact it would have to be an incredible job of making the fillet with no bonding to the shell itself.

If the shell is indeed intact, then the fix is far easier. Simply use an expanding eccentric, or some bonding to keep it in place. Or possibly a partial split of the shell at the ends and a hose clamp might have enough force to provide traction to keep the eccentric from moving.

BTW- Conspiratemu1 is right that for the collars to work the crack would need to sawed open to about a 2mm slot to provide for compression, same as I described if ears for bolts were to be welded on.

For anyone else with this design BB. Though I think it's a lousy design, it's probably OK as long as users understand that the bolts need to be tightened only enough to keep the eccentric from shifting, and they should avoid overtightening the bolts at the risk of causing this problem.