Relationship field search not retriving posts in admin

Turns out there is currently a conflict between Advanced Custom Fields Pro (5.2.8) and Relevanssi Premium (1.13.3) plugins.

If you enable the ‘Use search in admin’ function in Relevanssi then the problem described above appears. ACF support put the ‘blame’ in the Relevanssi plugin. I’m awaiting a reply from the developer if there is a work-around or solution. For now I have disabled Relevanssi search in the admin area and ACf now works as expected.