Having dealt with a 'countdown timer' on my RAM-Cummins 2500 I'm going to guess your engine will 'derate' at the conclusion of the countdown. The only solution is to have a dealer diagnose/flash the ECM to stop (or reset) the countdown. But that's a RAM pickup; your system could be different. In fact, I think Kubota diesels simply shut down at the conclusion of the countdown.
BTW, what's that orange(ish) symbol appearing in the lower-left of your dash, below the info screen? is that a 'regeneration in progress' lamp? That may have something to do with the entire issue.
As a newbie looking at your information screen, it appears as if you must have dealer service performed before 169 more minutes of operation.
DEF can degrade with time, it is sold new with a 'born on' date on the container iirc.
If you installed new DEF to replace defective/old DEF and that has fixed the problem, it's possible that a series of engine starts/warmups occurring WITHOUT the ECM/ECU (Engine Control Module/Engine Control Unit, whatever it's referred to in Kubota talk) detecting emissions problems could allow the engine service lamp to go off on its own (I doubt it). I'll bet that a 'symptom' like yours requires a US Govt-required visit to a DEALER so that all OEM emissions-related equipment can be inspected for performance (b/c it's a diesel with exhaust after-treatment).
The GOV is serious about diesel exhaust treatment. Please update this thread to let us know how you progress. Hope this helped, good luck!