Hello, thanks for answering.
The problem only appears when I update the themes/plugins (different ones every time) so I don′t know how I could test it with the method you mentioned (once I manually change the settings it stays that way until I must update anything).
But today I noticed something that didn′t happened in a long time, and that is problems with the lightbox. I use FirelighWP (free version) and it is having problems with this plugin.
In Other settings > Lightbox effects if I choose “none” it doesn′t show me the FirelighWP one, and if I choose any other that isn′t “Thickbox” it shows 2 lighboxs (this and the other plugin). With “tickbox” at least for now it seems to be working fine. ?
I have used this two plugins together for a long time and this is the first time that I notice any problem