Question about inheritance of exerted stigmas?

[maf]

I'm new to breeding tomatoes, just an amateur having a bit of fun really. Anyway, I made a cross last summer and when looking at the F1 plant today I noticed the flowers had exerted stigmas. The female parent of the cross definitely does not have exerted stigmas, but the male did iirc.

So I looked up the genes that cause exerted stigmas (main one is ex I think) and they all seemed to be recessive genes, meaning the trait should not show up in this F1. Can anyone explain this in terms of genetics? Or could the exerted stigmas I am seeing be caused by external factors such as environmental conditions?

[maf]

Thanks, thinking about it the flowers have been open a couple of days so could be post-fertilization, but "environmental (heat, uptake of N)" does sound likely too.

For reference here are the flowers: