Zinnia seed disease? – Reddit Post

I was rather impressed with myself, I kept a gorgeous fully double zinnia bloom near the peak of summer on the plant until it fully dried (6-8 weeks). The browned head was clipped and allowed to dry even further indoors (1 week). On removing the seeds this is what I saw: all seeds were flimsy and tan.. not a single viable seed in the entire head!

My instinct is this is fungal or bacterial.

Thoughts?