My experience has been the opposit.
Mt
M6800 had a problem where it would pop out of 2nd when going up a hill. I saw this with another
M6800 a few months earlier. I took it to the dealer, Hlavinka Equipment, and they drove it to confirm. We decided this would need Kubota approval, as it involved complete disasembly of the tranny.
Kubota approved the work and sent a new 1-2 shaft (first-second gear string) with all of the bearings, gears, gaskets, and parts for that shaft.
About three weeks later I dropped my tractor off and they had it finished in about 8 work days. It was involved, but the mechanic was well trained and had also done this repair on the other
M6800. I pressure washed it real good, which always helps the mechanic. After the mechanic was finished you could not tell by looking that a wrench had touched it. He even touched up the paint on the bolt heads. I felt lucky and very happy tht Kubota stood behind their product. It would prpobably be a $2500 repair if not under warranty. The three year powertrain warranty is great!
Don't sweat the small stuff. You could complain about the fuel tank, but a Chinese manufactureers would not even recall the tank, and when it did fail no spare would be available.