I don't know the OP's tractor, and I don't remember all the details of this thread.
BUT I do remember that some tractors, maybe even some Kubota models, will not allow the bucket to curl and loader to lift at the same time. One function or the other.
The ONLY reason I believe this is because of what I have read here at OTT. My loader will lift and curl at the same time, and I would not want one that did not. But those animals seem to be out there...
So I think saying that the OP's loader should be capable of lifting and curling the bucket at the same time could possibly be incorrect. But maybe Dan has knowledge of the OP's tractor, and it is one that should be able to curl and lift at the same time. Is this the case?
Just a question derived from knowledge gained at OTT.
That would be a function of the loader valve and I have never seen one that behaved like that. Even my ancient B1630 loader will dump and curl at the same time. According to KPAD his tractor would have had a LA300 on it. They provide no details on the valve other than it is a two spool monoblock valve with joystick control.
Loader valves are typically of the parallel circuit type where the spools all tee off the same pressure line allowing them to operate simultaneously. In that design it is possible for one actuator to
momentarily stall and then resume as the loads even out but its not an all or none behavior.
On the newer model loaders Kubota has the boom spool in series with the bucket spool. In this design the exhaust oil from the boom cylinder is fed back to the bucket spool so that the cylinders can't stall. The operation of my LA525 is extremely smooth and even and a noticeable improvement over the B1630.
One spool totally blocking the other would be a horrible loader design with no discernible benefit that I can see. Fully loading the bucket would be difficult and it would also make the joystick control useless. So I think it highly unlikely that is normal behavior and more likely a secondary effect of his 3pt problem.
But this is just more speculation - the testing should clear up some of the confusion as to what is actually happening.
Dan