PHP Warning: array_shift() expects parameter 1 to be array, object given in /var/www/html/lib/pkp/classes/core/PKPRouter.inc.php on line 485

Description of issue or problem I’m having:
I am attempting to list the installed plugins in the backend interface, Website Settings → Plugins, but the operation doesn’t complete (no console errors, i.e. 500 Internal Server Error is not present).

The only error in the logs is this:

PHP Warning:  array_shift() expects parameter 1 to be array, object given in /var/www/html/lib/pkp/classes/core/PKPRouter.inc.php on line 485

Steps I took leading up to the issue:
Went to the backend interface and attempted to list installed plugins. (I wanted to change some plugin settings)

What I tried to resolve the issue:
Looked in the forums for something similar but nothing specific to this error has been found.

Application Version - e.g., OJS 3.1.2:
OJS 3.3.0.10

Does anyone know of a solution to this?

Many thanks in advance.