Colorit yellow wont cure

Hello All

Regarding Colorit Photopolymer, Over the years I have used quite a
lot of it using various curing lights. The deeper colours take more
curing with thinner layers but generally I have no problems.

But I cant seem to get the basic yellow to cure. I have bought two
pots of it a few years apart and both only partly harden. I am using
the Colorit XS Fast Cure light.

Has anyone else used the Colorit Basic Yellow and had problems.If so
did you fix it and how ?If you’re using it without problems what
light are you using?

Thank you very much