The article alludes to two technical problems. One is density altitude; hot air is remarkably less dense than normal air. Redding is at 500', when it's 120°F out that's like 4400'. Not impossible for an ordinary helicopter but as the pilot says, you can't lift as much. The other problem is the electronics overheat.

Both seem like fixable problems: bigger engines and more heat-resistant electronics (possibly with active cooling). But you have to build for that. It's only going to keep getting worse.

(There may be a third problem with engine performance, I don't know about that.)