Ok, I've been racking my brain trying to figure this out, working on the latest zenphoto 1.5.6. php 7.3.8 on MAMP. The last bug to get ironed out before going live.
On a plain vanilla unmodified version of the zenpage theme (this also happens on other custom and default themes, but wanted to eliminate any variables), here's the issue:
Using the menu–manager plugin (which is brilliant), whenever I am in a zenpage news <i>category</i> the first item in the menu-manager menu becomes inactive (no href is printed, it's an empty LI with just text).
I've experimented with this a bit, no matter what the menu item is (page, news, link, gallery, album), it's always the <i>first</i> menu item which is inactive and link-less. It's only when I am in a zenpage <i>news category</i> page, everywhere else it's completely normal!
Any ideas what the issue could be? I'm totally stumped!