i am not sure to post this in the right topic, but i had a similar problem.
i registered 5 custom post types in the function.php but the 5th did not showed up in the backend on the left sided menu. Every registration beyond 4 is not visible!?
If you registered,lets say custom post type 5 and set it BEFORE custom post type 4 in the functions.php there just changing places in the backend, the 5 instead of 4 is visible, BUT in frontend the invisible backend custom post types are still active !
So regardless what you are registering in the functions only 4 are showing up in the backend… and the not visible, if you created content in the first place, are still active in the frontend.
i figured out the following:
menu.php
line 101
$_wp_last_object_menu = 30; // The index of the last top-level menu in the object menu group
Give it a bigger nummern as 25…
After editing the menu.php like this every registration beyond 4 is visible.
Maybe this could be a hint, because i assume that this may be a BUG…
