When I visit https://en.wikipedia.org/wiki/Special:Notifications I get the following error:
PHP fatal error:
Argument 1 passed to EchoEventPresentationModel::getTruncatedTitleText() must be an instance of Title, null given
It's the same irrespective of device and has been persistent for at least 3 days. I posted at WP:VPT and other's have reported it not being a problem for them. I can provide details of the notifications that I can see via the alarm buttons if that'd be helpful, but I can't see anything particularly unusual in them.