Yep. It's the same way that Babylon 5 was written as a 5-year story, then they thought they were being cancelled after the 4th and rushed to tell the original season 5 story quickly, then got a 5th season after all and sort of went, "Uhm. Hrm. Okay, now what? We already blew through what would've been season 5 on the back half of season 4..."
Unfortunately, while I love Bryke's work, they're apparently not as good at condensing story as JMS was. I expect the Amon story would've been a lot stronger if they'd had two full seasons to tell it in instead, and had been able to have Korra have to really go on a journey of self-discovery to figure out how to cure chi-blocking... or to come to grips with the idea that she couldn't, which almost might've been a more interesting tale. But in fairness, as much as the rushed ending was annoying, I also think it would've been way more annoying if they'd kept to that two-season arc and then been cut off halfway through, never finishing the story. So I understand how they got there.