In "Call to Arms", Dukat makes no mention of this treaty, which could mean that the Union seceded from it, upon joining the Dominion. However, the Bajoran-Dominion nonaggression pact seems to have served the purpose of maintaining peace between Cardassia and Bajor.
In the original version of DS9 Season 3's "Life Support", the political issues which, later in the development of the episode, became the Bajoran-Cardassian Treaty were peace negotiations between the Federation and the Romulan Star Empire, as well as the elimination of the Romulan Neutral Zone. (Cinefantastique, Vol. 27, No. 4/5, p. 106) When peace with the Romulans was deemed too inconsequential for Star Trek: Deep Space Nine and insufficiently compelling, the Cardassians and Bajorans instead became the two negotiating parties. Commented Ronald D. Moore, "It became more of a Deep Space Nine story. Suddenly we had some real stakes." Also, whereas the original form of the story had the peace negotiations happening all off-camera, this was evidently changed too. (Star Trek: Deep Space Nine Companion, pp. 205 & 204)