I am casting some very small parts (3mm diameter cylinders) using Gedeo crystal resin, which is a 2-part clear epoxy. I use a mould made with CS2 condensation cure silicone. It works quite well, except for two problems: I often get bubbles in the finished parts, even though I take great care to exclude them and I degas the resin before pouring. Secondly, the silicone rubber discolours and eventually becomes non-flexible and starts to come away when I take the parts out. I get maybe 7 uses from one mould before I have to discard it.
I will try to attach an image so you can see what I mean. The discoloration is definitely caused by some reaction between resin and silicone.

Has anyone experienced this problem? Would using a release agent help? Or a different silicone / epoxy? I like the Gedeo stuff because it is very runny and it sets properly even in such tiny amounts.