Goofs

When Journey signs her name in "invisible" ink, she starts to sign, then moves the pen away, before returning to the paper to finish. Yet her signature is a perfect single entity.

Jeronicus never takes suit against Gustafoson for stealing any of the intentions.

It is noted in the preamble he tried to take action, but couldn't get anyone to believe him as Gustafson had taken the only proof. Even if he could have found a lawyer willing to take him on, it's unlikely a judge would have allowed a suit to go forward without tangible evidence to back up his claim.

Without the proper training and education, it's unlikely Gustafson would have been successful.

Jeronicus is the most gifted and popular toymaker-inventor in this world, but that doesn't mean he's the only one. It's also possible his book of inventions contained all the detailed instructions a person would need to be able to successfully copy them without ever understanding how they work or learning to craft anything of their own. A clue being in that Gustafson had only one unique invention after thirty years of trying, and still couldn't make it function.