When I visit https://en.wiktionary.org/wiki/Prima while logged in, I get the following error message:

[XMx9RwpAMFsAADWNXh4AAABA] 2019-05-03 17:41:27: Fatal exception of type "Wikimedia\Assert\ParameterAssertionException"

This seems to occur every single time I load the (non-existent) page. It does not occur on other titles I've tried. Further, it does not seem to occur while logged out of my account.