@echoleaf – The page with the “3 galleries with a single image” appears to working as I would expect it to without issue navigating through the images to the albums, then to the galleries and finally opening the Lightbox effect you have selected.
As to the first issue you raised, this can be from a few different issues. When you review the inserted display is it still showing the source items you selected? There could also be an issue with a custom (NextGEN Legacy?) template being used for the display that may no longer be correctly rendering.
The last option which is more involved to test is for possible conflicts with another active plugin or the current theme. Have you tried deactivating all of your plugins, clearing your browser cache (and site caches if you are using a caching plugin), then reactivating the NextGEN plugin?
If this fixes the problem then it was likely one of the deactivated plugins that was causing an issue. Now, retrace your steps activating each plugin and re-checking to see if the problem returns. If it does then that last activated plugin was probably the one. Keep reactivating and in most cases it is also best to keep checking after each plugin, sometimes there may be more than one plugin on a site that will create an issue. If you do find one (or more) plugins causing this problem we would greatly appreciate your feedback on them so the developers may address them as soon as they can.
Also to note, in rare cases it may be the theme itself that is causing a conflict so while you have just the NextGEN plugin activated you might consider temporarily switching to one of the default WordPress Twenty series themes and see if this corrects the issue as well.
If the problem still persists after all of this we would still want to know, even more so, as we will still want to sort out the issue and may need additional details.
Thanks!
– Cais.