Show more link renders incorrect filter

[lazyfrosch]

When accessing events via host or service detailview extension (or possibly compact view as well), the rendered URL for "Show more" causes an Icinga Exception when loading the page:

eventdb/events?host_name=host&sort=priority&dir=asc&((ack=0&priority!=8&priority!=7&priority!=6))

Error:

Method Icinga\Module\Eventdb\Forms\Events\SeverityFilterForm::__toString() must not throw an exception, caught Error: Call to undefined method Icinga\Data\Filter\FilterAnd::getColumn()

#0 [internal function]: Icinga\Application\Web->Icinga\Application\{closure}()
#1 {main}

Versions

Icinga Web 2: 2.6.4