Loose bolts will cause cracks from the shock loads the loader exerts. Initial small fractures, getting severe after a few attempts to tighten. I suspect the parts cost are less than the labor, hence the dealer offer to supply parts.
From the photo posted, it looks like the hole in the bracket is much larger than the shank of the bolt.
If there is a lot of clearance between the bolt shank and the hole in the bracket, the bolts will never stay tight.
The relative movement between the bolt and the bracket will work things loose no matter how tight you torque it and the use of Locktite.