I'm having problem adding images to galleries. After clicking "Manage Gallery" I try to add some images already uploaded to the media library. Sometimes I can insert them to the gallery and some times not. If everything works as it should I can just close the media library popup after clicking "Insert" and click "Update Gallery". But sometimes when I click "Insert" it inserts the image into the content area of the post/page and not to the gallery. The issue is with already uploaded images, images I upload for the first time always work. But already uploaded images dont (some times).
Why is that? I'm using v.1.5 of the plugin.