Vertex functor silently fails and reject all subsequent events

When using functors related to the vertex position in the MCParticleFilter on all MCParticles, none of the events pass the cut, even when wrapped inside an F.VALUE_OR @ clause which should cause the events to pass in the case of no vertex. The filter, however, does work when it is restricted to those candidates which have a decay.

A 'minimal' reproducer can be found here: https://gitlab.cern.ch/-/snippets/3350

If there is some common behaviour that makes functors always return false when there is a single failure, this might need reconsideration - it could mean that one single failed vertex fit for particles can result in rejections for subsequent 'good' candidates.