I have noticed the same thing Hemlady, I figured the seeds were just bad even though the seemed firm when stored.
In the last few years I have added a piece of bleached printer paper with the seeds while storing them in the crisper, the paper will take on a pink/purple cast if any mold appears.
I check seeds every week or so.
The seeds get firm tested again when place in the auction bag, and one last time before I mail them out.
The two most important things for me as a seller, the seeds be true to the cross, and for the seeds to be of high quality.
Ed, auction ID "gramps"