Linguist's perspective.
"Deployment" has become correct through use. It is, however, a malapropism.
"Deployment" is a verbal noun; we say "THE deployment of troops" etc.
"Déployant(e)" is the present participle used adjectivally. "Une boucle déployante" is the French expression, literally meaning "an unfolding buckle" in the sense of "a buckle that unfolds".
"Le déploiement" has a very similar meaning to the English "deployment"; unsurprisingly, as the English is derived from it.
I am happy to be proved wrong, but I believe that no French speaker would say "une boucle déploiement".
It would be much simpler were we to call it, in plain English, a folding clasp. It's interesting also to note that the French think of it as "unfolding", whereas we would automatically think the reverse in English.
I fully accept that it will be called a deployment clasp, though I will never refer to it as such, and it will continue to jar with me a little because it is grammatically incorrect in its language of origin. Or perhaps one should say "mal à propos", hence my use of the term "malapropism". Technically, it is what we refer to as a cross-linguistic malapropism.
However, does anyone really mind? No, and I think it is perfectly reasonable for anyone who doesn't have a degree or at least considerable proficiency in French not to know that. So carry on deploying by all means. You're wrong, but you're forgiven.