If you enter the same seed value and open the world, you will be able to obtain the blacksmith mold as usual.However, in the world I am currently playing, even if I search for over 100 suspicious gravels in 4 ruins, no blacksmith mold will appear. You can get pot fragments, but only the blacksmith type is 0%.
This issue is still unresolved even with PlayStation version 1.21.1. I hope it will be fixed soon.