Yes! I'll write this for others that might need to do the same and for you so it's clearer (:
For work I'm making a cinematic, the particularity is that they needed to have exactly 80 frames exported singularly as images.
I made 3 skeletons: one for the background (it had a little parallax effect), one for the title (it had to bounce), one for the animal character (it waved and jumped). And just one animation.
So I went to export > PNG and if I select a folder Spine exports that one animation separately for each skeleton, a thing that I didn't need for my case.
If I don't select a folder and do exactly the same export, Spine exports all the 3 skeletons into one sequence animation.
SO in first case I got this:
And in second case I got the sequence I needed:
(notice how in this case the files are named)
Reading in the guide (there are no mentions to this) and the twisted way I obtained what I needed make me think it might be a bug, yet I think it's a great feature that has been really helpful in my case that I'd love to be able to use again (: