No language has "no mistakes".
For instance, let's take a language like Scala, which appeared 20 years ago. Has it avoided mistakes of the past? Or lets take Rust, which appeared 8 years ago. Is it "perfect"? Same with Moonbit; it will make tradeoffs and mistakes and whatnot.
Mistakes are not always technical in nature either. They can be mistakes in positioning, strategy, community, governance, poor documentation, etc.