tghattaq writes:

Can anyone advise me how to avoid this occasional surface cracking on
the profile?

Cracking comes from stress. Is this induced in the casting itself, such as
from shrinkage during curing, or is it from being bonded to another
structure which moves?

Do you use a polymer admix?

I'm curious how you make these molds. What patterns from what source, what
materials, what process.