Wayne, your problem is downright curious to me, without seeing the holster.

The hamner nose is supposed to rest in notches on cylinder, preventing rotation, until hammer eased back...which is what happened in front pocket with tight fitting jeans not only the gun often in a bind.

And kydex on the draw would pull hammer more firmly against cylinder (again, no idea of holster coverage). If the holster involves the hammer, it might be that insertion is what is easing back hammer and freeing cylinder. Keeping thumb pressure on back of hammer while inserting would likely prevent that latter thing.

I just make sure the gun is in nothing which can push back on hammer, which seems can also happen inside a pocket holster in a tight spot, so gun not put in tight spots, as I learned with the jeans.Then, it seems to stay as inert as a small rock and no need of extra safeties to push or whatever.