Keep an eye on it. If you notice issues, log it and call the dealer. "Logging" meaning a piece of notebook paper, or whatever, with notes written down regarding the issue at hand. This comes in handy with intermittent issues.
I could venture to guess that the sending unit is corroded. These tractors are shipped over here on a big boat, exposed to salty air, and then they sometimes sit on dealer lot for a length of time, without any fuel in them. So the combination can cause some corrosion on bare metal parts-and the sending unit IS bare metal. MX's haven't' been too much of an issue but L's have been in the past, replaced a ton of sending units. Those and BX's both.
Just keep an eye on it and don't let it go out of warranty if you continue to have issues. Extended warranty won't help with it either, neither will powertrain (3rd year). It's not considered a powertrain part nor is it considered a major electrical component. Kubota usually won't replace them once over the 2 year mark. I haven't done an MX sending unit in a while but I HAVE done an L4701 recently and it wasn't real easy to get it out. Lot of disassembly of parts behind the dash to get to it.