Thanks for describing the issue and for posting screenshots.
In your screenshot it seems as if there are no coordinates assigned to the images, but that the coordinate system of the images is set to WGS 84/UTM zone 30N:
This explains why there are only green and no blue camera icons in the second screenshot, as only the optimized positions are displayed (all initial positions being at (0,0,0)). I think this explains why the end up reversed, as there is no reference which can be used to correctly orient the project.
If you have the image coordinates adding them should solve the issue. If you do not have them, I would modify the image coordinate system (and output coordinate system) to “Arbitrary” and then add an orientation constraint to the project if it is still reversed.
Here are articles that should be helpful:
Keep us posted if you can fix the project or need further help.