Very interesting... I would have agreed with
@stiickygreen. I did find one different forum post with someone asking about seed viability. In the post quite a few people said the seeds will still sprout. But most said they weren't sure of the quality or safety of the end product. So that kind of made me think seeds are stronger than I expected in regards to a butane soak. I wouldn't have thought so though.
I sifted through some scientific articles as well but couldnt find any on the permeability of butane and seed shells. Most of the articles were in relation to more naturally found substances like water/atmospheric gases.
Definitely would be curious to see your findings if you do try it out.