I have a L3560 as well. My regen happened about the same hour mark as you. I also got the P2414 code, but I did not equate it with the regen process. Although it did happen after the 1st regen, there was a time lag and it was not during the same use (it it showed up later and I was working it hard). Dealer had to call the Kubota rep to find out what it was, and he told him to pull the EGR and inspect it for soot. He said that is not likely the problem, and don't spend a lot of time on it... just change it out. If it's bad, it's bad. It reset after shutting it down (but code will still shows in the error log until dealer reset) so I can use it, and they said I could continue to use it without damaging anything. So I agreed I will bring it in to get fixed when I need to bring it in for a new front snowblower to get mounted unless it happens a lot and gets annoying... but it has not happened again (but haven't worked it quite that hard since either).
From the searching I have done, the only time this has showed up as a problem is on the L3560. The service manager had never heard of it, and that code was not showing up anywhere that he could find. He had to call the rep to find out what the code was. Based on their response, and that I could not find any other instance that was not an L3560; it almost sounds like a problem with some of the EGR's on this model (but that is speculation on my part). The response back to me seemed pretty cut and dry.
Let me know if you hear anything differently.
Pat