It's a 2016, meaning it was sold around 2016? Kubota tractors do not have year models officially.
If so, it was 2016-ish, the limited warranty is probably expired by now (even if it was extended warranty?). Warranty (remember that word that is in front of it? Limited) doesn't last forever unfortunately. If a repair is made and kubota pays for it, and then the warranty expires. Let's say for instance a month later the same complaint comes back up. There are several choices. The tractor is now out of warranty and getting Kubota to help with it is close to impossible (not totally but they've changed policy in the last year or so and "goodwill" requires partial participation from the dealer and customer). That doesn't set well with me or anyone else but that's the way they do it, and will continue to do it--until things change. Option 1, return it to dealer who did the work and ask them to find the source of the problem and call you with estimate. Option 2, tell them to just fix it. Option 3, (my suggestion) find the source of the failure, then call you with what it is and why. At that point you will know if it's something that the shop did or if it was totally unrelated. There are a hundred places for oil to leak out of so if you had it in for an axle seal once and now it's a hydraulic hose leaking, they are gonna say it's unrelated, and they might not be wrong. See this is where nobody wins, not the shop, not the tech, not kubota, and certainly not the consumer. I deal with it all the time. But we have to remember a lot of things. Warranty has limitations set forth by the manufacturer (does anyone read the booklet?). Also, these and every other machine is comprised of many different subsystems that kind of intertwine with each other to make the machine work. What's that mean? That means if you replace a spark plug and a week later the blade bolt comes loose, it will be impossible to prove that the person that replaced the spark plug is at fault for the blade issue.
When I did service management, and thank goodness I don't anymore, most people would not even begin to fathom the amount of money that the shop pays out on a weekly basis to fix stupid stuff like that in the name of customer service. Basically, at one time, it was costing us $5300 a WEEK (on average) to keep people happy. Yeah sometimes it was the shop's fault. Most of the time (large majority) it was not, it was simply a function of "well I had it in for you to check the tires last week and now the steering wheel is loose"....that kinda stuff. That's a lot of money to piss away, but trust me, they don't just eat it. There's a reason shop labor rates are as high as they are and they keep going up all the time. Car dealers have everyone spoiled but did you ever stop to ask yourself why cars cost $50K+? Because half of that pays for that purdy dealer and pays the dumb blonde behind the service counter's wages, just so that you (the customer) feels all happy inside like you got a "good deal". Tractor dealers haven't caught up with that yet but the way things are going, it won't be long....
/rant