My only experience with growth inhibitors was so long ago that I can't remeber many details. But what I do recall is that the company for whom I was growing seed wheat was quite happy to encourage us as growers to use the stuff, mainly because it was another input that they could sell us! However, since it was their seed stock that was a risk, I can't imagine that it could have been harmful to the seed viability, or they would have been liable for something that they had recommended.
Since then, the wheat varieties have been selected for better standibility and straw stiffeners have become a thing of the past, to my knowledge.