That was because Yu Fei had only been the chief designer for a month and was relatively inexperienced. Thus, he had a problem when arranging work.
It was a huge and cumbersome task to divide the content of a game into four parts and update it in turn.
He had to keep the original basic design. Otherwise, the game might be stuck and collapse for various unknown reasons, bringing players a bad experience. They might not even be able to operate it.
What's more, the various scenes, monsters, gameplay and mechanisms in the game were closely related. He had to be careful when disassembling them.
In addition, Yu Fei's plan had not been explained in detail, so the designer in charge of disassembly ignored the automatic block mechanism of the demon sword under the huge workload, letting it be updated in the first part with the lower level mechanism.
This looked inconspicuous, but it caused a suffocating chain reaction.