UPDATE: I am very pleased to report that I exchanged several phone calls with BXpanded today and that they were about as helpful as any company could possibly be when something goes wrong. They repeatedly apologized and assured me that they would take care of everything asap.
During on our conversation, they shared a few thoughts on how this situation happened; First, my tractor is very new and that I may have a slightly updated variation of the BH77 thumb. Second, the pin hole on my buckets is in a new position that they have not encountered before. Third, Kubota equipment is hand assembled and hand welded so the tolerances are a bit less precise than say the automotive industry. Fourth, all of their items are hand assembled and hand welded and while they do try to keep the specs tight, things do slip by on occasion.
After hearing the above points, they were happy when I offered to send them any pictures and measurements of my tractor, buckets, backhoe, pins, etc that would help them revise the design.
For starters, they will weld up a new front pin that fits my buckets exactly like the one in their instruction manual. This will require the handle to be clocked approx. 120 degrees counter clockwise so that it matches up exactly to the linchpin hole. I encouraged them to offer this as an option on their website for those who have newer buckets.
Here's an example of how it should look:
Here's how my pin looks today:
They are also going to update the design slightly based on the measurements that I gave them and the angles they were able to harvest from the pictures I sent them. This will involve shifting the bucket slightly towards the back of the tractor. If you look carefully at this picture, the yellow circles show the contact between the quick attach adapter and the thumb:
Its critical that this attachment point stay close to the factory position as any extension of the bucket will lower the working force of the hoe due to a loss in mechanical advantage.
This is my fourth or fifth purchase from BXpanded and the very first time that I have ever had an issue. I cant speak for their lead times or communication practices prior to the sale but their communication with me on this issue has been very good so far.