I had this issue as well but what I do with all my bags - since the Antigona is basically flawless except for the pesky strap - is either put a cheap matching keychain ring around both connecting parts of the bag (the bag ring and the strap ring - do not do this with a fresh manicure) or do the same with a keychain that works as a bag charm. Remember it has to go around BOTH the connector piece on the bag and the connector piece on the strap. Then connect them anyways. It acts as insurance if they disconnect. Here are the ones I used. I took them off my Antigona mini since I’m selling it.
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The top one is the cheap ring which you almost never notice. It is a pain to put on and take off and you may need a butter knife. The other two are easy to put on but obviously cost a little more. Alternatively you can just connect the two pieces and put clear take to close up one of the straps.